Salaries, incentives and intellectual output of teachers in public universities in Colombia

Salarios, incentivos y producción intelectual docente en la universidad pública en Colombia*

Salários, incentivos e produção intelectual docente na universidade pública em Colômbia

Jhon Alexánder Méndez Sayago**

Leonardo Vera Azaf***

Research article

Date of reception: 16 oct 2014

Date of approval: 25 jun 2015

 

Abstract

In this article the determinants of the intellectual productivity of professors in public universities in Colombia are studied, focusing on the effect of salary incentives on intellectual productivity and the resulting salary. Based on information from the teaching staff of the Universidad del Valle between the years 2004-2012, econometric models of the lifecycle of university professors were estimated to quantify these effects. An important and significant effect of the present value of the salary point was found, but no positive effect was found on wages due to intellectual output. The effect of incentives according to the age of the researcher and the impact of percentage increases in the value of the salary were also calculated.

Keywords: intellectual output, life cycle model, university professor, Tobit model, incentive.

JEL: C24, J24

Resumen

 

En este artículo se estudian los determinantes de la productividad intelectual de los profesores de la universidad pública en Colombia, enfocándose en el efecto del incentivo salarial por productividad intelectual y el efecto salario. A partir de información del cuerpo de profesores de la Universidad del Valle, comprendida entre los años 2004-2012, se estimaron modelos econométricos de ciclo de vida del profesor universitario para cuantificar dichos efectos. Se encontró un efecto importante y significativo del valor presente del punto salarial, pero no se halló efecto positivo del salario sobre la producción intelectual. También se calculó el efecto del incentivo en función de la edad del investigador y el impacto de incrementos porcentuales en el valor del punto salarial.

Palabras clave: producción intelectual, modelo de ciclo de vida, profesor universitario, modelo Tobit, incentivo.

Resumo

Este artigo discute os determinantes da produtividade intelectual de professores de universidades públicas na Colômbia, concentrando-se sobre o efeito da produtividade intelectual salário de incentivo e efeito salário são estudados. A partir de informações do corpo docente da Universidad del Valle, entre os anos de 2004-2012, professor econométrico modelos de ciclo de vida universitária para quantificar esses efeitos foram estimados. Um efeito importante e significativo do valor presente do ponto de salário foi encontrado, mas nenhum efeito positivo dos salários foi encontrado na produção intelectual. O efeito do incentivo, dependendo da idade do investigador e do impacto de percentagens de aumento no valor do ponto de salário também foi calculada.

Palavras-chave: produção intelectual, modelo de ciclo de vida, professor universidade, modelo Tobit, incentivo.

 

INTRODUCTION

As indicated by Baccini, Barabesi, Cioni, and Pisani (2014) and Obembe (2012), the study of scientific productivity and of the factors associated with it, has been a topic that has attracted the attention of researchers, particularly in the last 30 years.

Stephan (2010) expresses three reasons for which the economy of the sciences has been gaining ground in the last years. Firstly, science has been identified as a source of growth, which has been confirmed by the recent advances in information technologies. This situation has contributed significantly to the growth of the service sectors in recent years. Advances in medical research have also led to an increase in work and life expectancy. The second reason is related to the topic of appropriation of knowledge, that is to say, once knowledge is produced and made public, no one can be excluded from its use. Therefore, the failure of economies when trying to produce the optimal amount of knowledge considering it a public good is a topic of importance for the economists. Finally, the public nature of research and the spillover inherent in a system of such characteristics is fundamental for the concept of the theory of endogenous growth (Archibugi & Coco, 2004). 

Perozo, Arteaga and Fuenmayor (2008) argue that research has become the process that contributes the most to the development of countries, which explains why powerful countries invest high percentages of their gross domestic product (GDP) in research and development, achieving great scientific and technological advances. This situation leads to the affirmation that research is recognized globally as a pillar of the acquisition of new knowledge and technologies. This complex activity involves companies, institutions, national universities, and international collaboration networks so as to obtain better results.

The current demands of society also force professors, from diverse scientific standpoints, to seek concrete solutions to the problems that the educational context in which they develop requires. It is from there that the idea arises that universities should be understood as centers of intellectual output, taking into account that, in the academic context, it is research that generates knowledge. In a knowledge society, the creation of new knowledge is indispensable, and it is the university professor who is called to produce and revise it. In fact, the results of investigations help to improve the praxis of the teacher in a permanent way and, therefore, research represents a primary activity in universities.

Facing these changes, Colombian universities, especially public universities and the most well-known private universities, that traditionally focused on teaching, changed their perspective and developed policies that make research one of their priorities, offering incentives to publications and expecting that through them, teachers would generate knowledge and circulate it in national and international indexed journals, research books, or take part in conferences and academic events (Guzmán & Trujillo, 2011).

In this incentive policy, basically two strategies can be identified. The first is implementing starting salaries which are relatively low that increase based on intellectual output. In the second, relatively high starting salaries are offered with premiums for intellectual output during a limited period, generally, of one year.

One of the main problems that public universities in Colombia face in the recruitment of new professors are the legal restrictions they have in setting a salary that is attractive to the most talented candidates in the market[1]. Nevertheless, public universities also offer advantages that motivate professors with research abilities to join public universities: 1) they do not demand exclusive contracts, 2) depending on labor seniority, experience and, above all, productivity, a public university professor may earn as much as a private university professor.

The problem is that once a teacher is hired, given their low salary, they could opt for other activities that generate income to the detriment of the time dedicated to research, which would affect intellectual output, which is one of the aims of the university management as that brings prestige to the institution.

This article intends to establish which of the two alternatives is more effective as an instrument for stimulating the intellectual output of teachers. To achieve this aim, the article researches the determinants of intellectual productivity of professors in public universities in Colombia, focusing on the effect of incentive pay for intellectual productivity and the resulting salary.

In order to understand the relationship between salary, incentive pay, and intellectual output, the article presents an adaptation in discrete time of the Levin and Stephan life cycle model (1991). The innovation is that the future salary of the researcher professor depends on publications during their life cycle, and not on their prestige.

Afterwards, from the information provided by the body of professors from the Universidad del Valle between 2004-2012, the life cycle model of a university professor was estimated econometrically so as to quantify the effects of salary and incentive pay on intellectual output.

The article is organized as follows: in the first section, a revision of the state of the situation is presented, which gives an account of the main determinants of scientific production and makes a revision of the theoretical life cycle models which attempt to explain the dynamic of the productivity of a researcher through time. In the second section, the contractual relationship between the public university and the university professor is analyzed as from agency theory, with emphasis on incentives as a stimulus for intellectual output. In section three, a life cycle model for university professors in public universities in Colombia is developed, which unveils the impact of salary and incentive pay on their intellectual output. In section four, data and descriptive statistics are presented. In section five, an econometric estimation of the life cycle model is realized. In section six, the results are analyzed so as to finally present the conclusions.

REVISION OF THE LITERATURE

Print and Hattie (1997) define scientific production as the group of studies developed by academics in universities and related contexts during a certain period of time. For Piedra and Martínez (2007), scientific production is understood as the materialized part of the knowledge that was generated, and for this reason, many refer to it as the results in the form of publications of research works; such as, for example, articles published in international, local or national journals, books or book chapters, presentations in conferences, documents, etc.

Others place scientific production in a broader setting than the mere publication. According to that point of view, “the theses that were defended, but not yet published, the works presented in conferences, colloquiums, and symposiums, classes, laboratory works finished, but not published, including field work; all the above is scientific production” (Piedra & Martínez, 2007, p. 3).

Even recognizing that scientific productivity covers the whole of the research produced by scientists, its measurable element is the number of publications produced by a certain author, institution or country. Manjarrés (2009) presents arguments such as the peer review of Fielden and Gibbons (1991), the preferences of researchers, such as Crane (1965) and Merton (1968), the homogenization of Paasi (2005), and the perception of prestige of the journal of Miller and Serzan (1984), so as to conclude that the number of articles published by a professor in international journals is the principle measure of scientific production of the present day.

In regard to this, in Colombia, university professors and magazine editors have spoken against the way of socializing knowledge imposed by the standards of mainstream science, which leads to the marginalization of Colombian academic output and scientific publications.

After discussing the concept of scientific productivity, the state-of-the-art of the different forms of analysis of scientific productivity can be explored. Baccini et al. (2014) distinguish two alternative approximations: the first one focuses on the fundamental laws of frequency distribution of the number of publications (or quotes), whereas the second one has the objective of identifying the determinants of intellectual output.

Baccini et al. (2014) also mention that the first approximation has its origin in the pioneering study of Lotka (1926) on the frequency distribution of the scientific performance of chemists and physicists. Lokta concludes that 60% of these individuals make only one contribution throughout their lives, so that the number of authors with  contributions is  of those who make only one.

Furthermore, Baccini et al. (2013) quote the arguments of other researchers that attempt to show the differences among researchers:

The sacred-spark hypothesis, proposed by Allison and Stewart (1974) and David (1994), according to which the differences in productivity reflect the unequal and predetermined abilities of the researchers.

The Matthew-effect hypothesis, developed by Merton (1968), which suggests that it is easier for well-known researchers to publish their works than for  lesser known researchers, despite that the latter have contributions of equivalent quality.

Cole and Cole (1973) put forward the cumulative advantage hypothesis. The idea is that the recognition received at an early stage of a researcher’s career can be reinforced with time, as this allows them easier access to the resources necessary for research. This means that any advantage will be cumulative.

The second approximation directs its attention to identifying the individual and collective determinants of scientific productivity. The former refer to the individual attributes of the researcher (sex, age, field, etc.) and the latter are factors related to the environment in which the researcher works and the general reward system of the science. Manjarrés (2009) makes a distinction between the academic and socioeconomic environment, the latter being understood as the effect of financing coming from industrial agents and, in general, the relationship between university and business.

The objective of this section is to revise the literature related to the determinants of intellectual productivity by exploring the approaches based mainly on the study of individual characteristics and the academic context of the professor, because in Colombia the relationship between public universities and businesses is very weak. As Gutiérrez and Berrío (2011) state, the reality of that relationship in Colombia is each to their own.

Individual factors

The bibliography regarding the determinants of the scientific productivity of university professors includes, as explanatory variables, the individual characteristics of the academics, such as age, sex, position within the institution, and scientific field. The relationship between age and scientific productivity is the aspect that has most caught the attention of economists and sociologists, giving origin to the denominated life cycle models of the researchers.

Although the results obtained have been diverse, several studies indicate the existence of a non-linear relationship, in the shape of an inverted U, between the age and productivity of researchers (Bayer & Dutton, 1977; Cole, 1979; Zuckerman & Merton, 1972; Weiss & Lillard, 1982; Levin & Stephan, 1991; González & Veloso, 2007). It has also been pointed out that the peak of productivity is heterogeneous; it varies according to the field of expertise of the professor (Levin & Stephan, 1989). Lehman (1958, 1960) found that scientists of the hard sciences reach a peak of productivity sooner than those who belong to other disciplines. Others have discovered that the productivity curve has two peaks (Bayer & Dutton, 1977). On the other hand, Allison and Stewart (1974) noted a positive correlation between inequality in productivity and age groups, so that, the greater the age, the greater the differences among the researchers.

The first studies on the determining factors of scientific productivity were based on cross-sectional data and attempted to explain the productivity accumulated during a certain period of time. However, the results are questioned for the impossibility of distinguishing between the supposed effect of age and that which would correspond to the generational cohort. Later on, the availability of longitudinal data allowed for the analysis of the productivity of researchers of a same cohort with different ages, as they get older, thus separating the two effects (Manjarrés, 2009).

Rauber and Ursprung (2008) based on information from German academic economists, found differences between different cohorts in the relationship between age and intellectual productivity. In the researchers of greater age, productivity is maintained throughout their lives, while in the young, a quite pronounced inverted U shape is observed.

Analyzing the determinants of productivity observed during the period 1995-2000, of a sample of 1134 researchers at the Louis Pasteur University in France, Carayol and Matt (2006) found from a Tobit regression that age negatively affects productivity, but they reject the inverted U shape.

Given the importance that the age factor has in the explanation of academic productivity for this research project, this section is dedicated to the revision of the main economic life cycle models that contribute to understanding said relationship.

Professional experience can also be considered to be a factor that affects intellectual output. Rebne (1990) and Goodwin & Sauer (1995) concluded that the maximum performance of a researcher occurs within the first ten years of work and tends to decrease after 25 or 30 years of academic activity.

It has also been indicated that the position the professor occupies within the institution can be a determining factor in explaining their scientific productivity. Knorr, Mittermeier, Aichholzer and Waller (1979) found that when the effect exerted by carrying out administrative chores is controlled, age ceases to be a significant factor.

Many studies have shown that intellectual productivity tends to increase depending on the position of the individual in the academic hierarchy. Manjarrés (2009) cites Cole and Cole (1973), Long (1978), and Carayol & Matt (2006) who discovered that the professors with higher rank within an institution, for example full-time teachers, have greater productivity than teachers of lower rank (junior or assistant).

A study by Aksnes, Rorstad, Piro and Sivertsen (2011) indicated that full-time teachers are the most productive. On average, male professors publish 9.5 publications in a period of four years, followed by associate professors with 4.8 publications and doctors 4.5 publications, whereas doctorate students have the lowest productivity (2.9 publications).  With respect to the differences, Kyvik (1991) observed that professors, being leaders of research groups, appear in all publications whereas doctorate students only appear in the ones they are the authors of.

It should be taken into consideration that the incorporation of variables, such as academic rank or professional experience, may generate multicollinearity problems with the age variable, modifying its explanatory capacity or altering the direction of its influence (Carayol & Matt, 2006).

Another personal attribute associated with scientific productivity is sex. Many studies have found great differences between the sexes as regards intellectual productivity in favor of men (Aksnes et al., 2011b; Kyvik & Teigen, 1996; Cole & Zuckerman, 1984). For example, Aksnes et al. (2011b) discovered that in almost all age groups, men are more productive than women. Female scientists tend to publish generally between 20%-40% less than their male colleagues. In order to explain said difference, investigations have been carried out that include the marital status variable to try to explain intellectual productivity. The hypothesis is that married female researchers could be less productive given their domestic responsibilities. However, the evidence regarding this point is ambiguous (Reskin, 1978; Astin & Bayer, 1979).

Field of study is another of the classic factors that can determine scientific productivity. Dundar and Lewis (1998) found significant differences in the average number of articles published by academics in universities in the United States according to the academic discipline they belong to. The authors realized that while a professor representative of the social sciences published approximately 2.5 articles between 1988 and 1991, their colleagues in biology published 9 articles during the same period. However, Dundar and Lewis suggested that these results reflect the general differences in the publication trends between different areas rather than authentic differences as regards the levels of research activity per field.

Institutional factors 

Institutional factors also arise as possible determinants of scientific production. These factors are mainly related to the institution, the faculty, or the department where the professor works, or the group in which the scientist develops their research work According to Manjarrés, (2009, p. 62):

Policies and institutional objectives are the framework that underlies the evaluation processes of scientific performance and the foundation of the reward systems in science. In this sense, the distinctive features among the policies, objectives, or the emphasis of the university missions may generate different organizational cultures, which may have an effect on the scientific productivity of the professor.

In order to measure the influence of the characteristics of the institution or the department over intellectual productivity, Manjarrés (2009) cites Kyvik (1995), Bonaccorsi & Daraio (2003), Smeby & Try (2005) as authors who have included in their econometric models variables like department size. Jordan, Meador, and Walters (1989) have taken into account the public or private nature of the institution, and Creswell (1986) and Long (1978) have taken the prestige of the department or the institution into consideration.

It is supposed that larger organizations can accumulate more resources for research, which increases productivity. These accumulative effects may also be accompanied by economies of scale in scientific production. The results are not conclusive. While some studies find a positive relationship (Dundar & Lewis, 1998), others find little relation (Cohen, Florida & Goe, 1994) or only in some disciplines such as the natural sciences (Kyvik, 1995).

The relation between the number of teaching hours and productivity is not clearly determined. Whereas in some studies there appears to be a negative relationship in terms of opportunity cost (Fox, 1992) and in others the relationship is positive (Dundar & Lewis, 1998; Kyvik & Smeby, 1994).

Estimation techniques and unit of analysis

In the literature, different estimation methods are employed. When dealing with the productivity of count data, most of the studies opt for methods, such as that of Poisson, the negative binomial, and, in the case of proportions with many zeros in the dependent variable, the Hurdle model is chosen. The MCO method is also used with the dependent variable in logarithms and the Tobit model.

The most frequent unit of analysis in the analysis of intellectual productivity is the individual, but also studies on different levels can be identified, for example research group, department, faculties, and even territories (Smeby & Try, 2005; Bonaccorsi & Daraio, 2003; Dundar & Lewis, 1998).

Porter and Umbach (2001) demonstrate that the effect of age in a model that employs multilevel techniques significantly differs from those offered by an analysis model on an individual level. Smeby and Try (2005) find that the age of the researchers has a negative effect on productivity at an individual level, but that the average age in departments have positive effects in productivity on a group level. The argument used to defend their results is that older researchers take on tasks that support the research, such as the organization of seminars or motivation and supervision of young researchers who generate important externalities. Moreover, as reputation is based on the publications made and on professional contacts, older researchers have a greater capacity to attract financing, prestigious collaborations, and young researchers with better prospects.

SALARIES AND INCENTIVES FOR INTELLECTUAL OUTPUT IN PUBLIC UNIVERSITIES IN COLOMBIA

A contract is a set of rules that facilitate the cooperation and exchange carried out by rational economic agents because it creates the necessary incentives for the agents to make the transactions. In any economic interaction, two parts can be identified: the principal and the agent. The principal is the one who hires the agent to do a job. The employees (agents) commit to use their abilities to do the tasks that the employer (principal) asks them to do, and the employer commits to pay the employees and to maintain a favorable work environment  (Gorbaneff, 2003).

The Principal-Agent model allows the analysis of incentive policies related to research in public universities in Colombia to be undertaken. In the work contract that the university (principal) and the professors (agents) agree on, the latter commit to carrying out research, teaching, and extension activities. The contract includes a determined remuneration, and specifies the level of effort that is explicit in the academic workload of the professor, in terms of the hours that they agree to dedicate to research, teaching, and extension activities. The principal cannot directly observe the actions of the agent (actual time dedicated to research), so the professor’s fulfillment of the task is verified through the products that the professor hands in at the end of the academic period (Carvajalino & Ariza, 2008).

The university benefits when a professor publishes their intellectual output because this gives them recognition and status. Nevertheless, there are no effective control mechanisms that allow the university to directly influence the professor’s level of effort, as regards the quality of their intellectual output or their effort to receive recognition for their work. This creates the need for an incentives scheme that ensures that the professor makes the maximum effort in the research, so that the results benefit the university as well as the professor.

Decree 1279 of June 2002 is the norm that determines the salary and the academic incentives of a professorial career. It established the incentives for a professor’s intellectual output in public universities in Colombia. According to this norm, a professor’s salary is the result of multiplying the value of the salary point by the accumulated salary points that have been granted to the professor.

The value of the point is determined every year by the national Government and the number of points depends on the evaluation of the following factors:

·         Category within the professor pay scale

·         University studies

·         Certified experience

·         Academic production

·         Academic-administrative managerial activities

·         Outstanding performance in teaching practices and extension activities

The categories defined in the Decree 1279 for the professor pay scale are: auxiliary professor, assistant professor, associate professor, and tenured professor. To the degree that a professor ascends in the professor pay scale, they earn more salary points. A tenured professor can reach a maximum of 96 points. Professors ascend this scale depending on their intellectual abilities, merits for academic achievements, certified teaching experience, and intellectual output in their professional field or their subject of expertise.

The setting of the remuneration of university professors is also based in their training, and this is intended to stimulate professors to not stop at a certain level of education and to reward the investments that teachers make in human capital, in their intellectual development. For instance, a professor who holds a Master’s degree may receive 80 salary points for obtaining their doctorate and up to 10 additional points for each post doctorate.

The evaluation of certified experience in Decree 1279 gives more points when the candidate has worked in research institutions of science, technology, humanities, or pedagogy (37 points per year) than when a professor has worked in a university (4 points per year).

A professor’s intellectual output is valued in two different ways: through salary points and with bonuses.

 The value of salary points is set in article 10 of Decree 1279: publications in A1 type journals=15 points, in A2 type journals=12 points, in B type journals=8 points, in C type journals=3 points, according to the indexing system established by Colciencias; production of cinematographic or phonographic videos of international importance=12 points, of national impact=8 points; the publication of books as a result of an investigation=up to 20 points; the publication of essay books=up to 15 points per book; translation of books=up to 15 points; national and international awards=up to 15 points; patents= up to 25 points; technical production=up to 15 points per innovation; for adaptations=8 points; software production=up to 15 points.

Salary points for outstanding teaching practice are given taking into consideration the students’ evaluation of the professor. Outstanding performance in extension tasks is evaluated based on a document in which the professor supports the presence of the university before the community, the academic and social relevance of the service, its complexity and singularity, an evaluation of the activity by the community or the institution that benefited from the activity. The annual salary points assigned to outstanding professors in teaching practices and extension activities are: professor with tenure; up to 5 points, associate professor; up to 4 points, assistant professor; up to 3 points, and auxiliary professor; up to 2 points.

It is clear that Decree 1279 contains an incentive system to foster the intellectual output of professors in public universities. This incentive system rewards the professor’s intellectual output with salary points and brings more recognition to the university.  The amount of economic incentive (EI) corresponds to the current net value of the salary point.

 

Guzmán and Trujillo (2011) conclude that incentives for research have an effect mainly on young professors, who have recently joined the institution and whose time is partly devoted to research, for whom the cost of the effort of carrying out the research should be covered by the research incentive, so as to avoid that they only partake in teaching activities and instead divide their efforts between both activities at an affordable cost to society.

Carvajalino and Ariza (2008) developed a survey for professors of the Universidad Industrial de Santander, in order to capture the perception of the professors concerning the efficiency of incentives for research and their general motivation.

The survey showed that most of the professors consider that the motivation to belong to a research group lies in the possibility of development and personal academic recognition (70.73%). Another motivation is to ascend in the professor pay scale, for which more than half of the professors surveyed gave a high value. 65.85% of the professors consider that problem solving is a great motivator. And finally, 24.39% think that the main motivation is to get a pay raise or a bonus. The survey revealed that the economic incentive is not the main reason for professors to do research. The possibility of development and personal recognition as well as an improvement in the professor pay scale are arguments that support the hypothesis that professors do research because it improves their status within the university.

In the same survey, 14.63% of the professors consider that the university incentivizes research with pay raises, 19.51% of the faculty supposes that incentives are given through bonuses, 9.76% believe that the incentive comes from the distribution of the academic workload, 26.83% think that the incentive comes from academic distinctions, and 34.15% consider that the incentive is given through study commissions.

The survey revealed that less than 10% of the faculty find that the allocation of research hours of the academic workload is an incentive for research, that is to say that this mechanism of direct regulation for research does not work, according to the very same agent (professor).

 

LIFE CYCLE MODEL FOR PROFESSORS OF PUBLIC UNIVERSITIES IN COLOMBIA

Life cycle models of scientific researchers are intertemporal optimization models of the profit or income of the researcher, which relate the time dedicated to research and, thus, relate their research results with age. As their stock of knowledge gives them prestige, this depends on time dedicated to research. In these models the relation between said stock of knowledge and age is also obtained. Diamond’s (1984) pioneering article and the contributions of Levin & Stephan (1991) and Rauber & Ursprung (2005), among others, can be highlighted. In general terms, the cited life cycle models reveal the reason why variables such as the marginal return of research products, the marginal utility of solving a scientific puzzle, the rates of learning and the depreciation of knowledge, affect the researcher’s intellectual output and why it declines with age.

In this section, a life cycle model for professors in public universities in Colombia is formulated, assuming that they can divide their time between teaching in the public university, which is compulsory, research, and other alternative activities, for example, classes in a private university or consulting, which incorporates the opportunity cost of the time dedicated to research. The model is an adaptation in discrete time of the model by Levin and Stephan (1991). A modification is made because of the fact that future reward does not depend on the researcher’s prestige, but rather their expectation of future salary depends on the intellectual productivity accumulated during their whole academic life cycle.

As in Levin and Stephan (1991), it is assumed that the profit function of public university professors in Colombia has as its basis the status of the professor in the university community,Status_t,  and consumer goods X_t.

The  variable is calculated as a sum subtracted from present and past publications

 

The professor maximizes the current value of their profit during a period of time, T.

Subject to:

 

Where  y   are parameters of the temporal preference of the profit function and the status of the professor, and  is the interest rate. The equation (4) corresponds to the dynamic of the stock of knowledge  , which is updated according to the publications of the previous period , and accounting for a certain rate of knowledge depreciation . Equation (5) describes the dynamics of the assets , where is the price of . The variable  is the proportion of time invested in research, and  is the fraction that represents the time dedicated to working at another university or consulting, for which a payment is received , which is assumed to be exogenous to the research productivity of the professor. The term  is the salary for the period, based on the accumulated intellectual output up to the previous period. The VSP variable is the value of the salary point.

 The function of research production is identified as:

The choice variables are  and .  and  are assumed to be free. Table 1 contains the initial parameters for the simulation of the model. In Table 1, the relation between the values of the parameters based on the utility function is , in order to give more weight to the consumer goods than to the professor’s status in the university, and so that it is possible that the professor dedicates time to other activities that generate income.  The parameter is  so that the function of research production shows decreasing marginal returns in the stock of knowledge K. The values of the discount rates, knowledge update, and value of the salary point were assigned for the simulation to make sense. This implies that the relation between the initial and final salary is consistent with reality, and that the professor dedicates some fraction of their available time to other activities that generate income. The simulation spans 35 years, for an interval of ages of a representative professor between 31 and 65 years of age.

Table 1.  Values of the parameters for the simulation of the base line model

 

Parameters

Value

Profit Function

0,2

0,8

Output Function

b

0,8

Knowledge update

a

0,2

d

0,1

Discount rate

0,04

0,5

0,1

Others

3000

10000

100

2

Source: elaborated by the author

Table 2 shows the first simulation of the model. It is observed that, until the age of 51, the representative professor of the model dedicates more than one fraction ( ) of their time to research, and less to other activities that generate income, such as teaching at another university. However, with the passing of time, the current value of the incentive to publish drops, which means that the professor now decides, towards the end of their career, to dedicate more time to other activities ( ). The total production of a researcher during their life cycle is , the average time fraction dedicated to research is , and the average final salary is less than four times the initial salary.

Table 2. Simulation of the model – base line

Age

Status

X

Profit

A

K

P

W

OW

31

1,46

6,22

2,44

1,00

2,444

0,80

0,0

2

1,46

3000,0

1978,7

32

1,85

6,54

2,56

0,96

2,464

0,51

2781,9

2,238

1,12

3146,0

4871,4

33

2,03

6,88

2,62

0,92

2,427

0,48

5993,4

2,349

1,10

3257,6

5183,2

34

2,16

7,24

2,68

0,89

2,379

0,48

9330,8

2,445

1,14

3368,0

5165,0

35

2,28

7,62

2,72

0,85

2,329

0,49

12716,2

2,544

1,20

3482,3

5068,1

36

2,40

8,02

2,77

0,82

2,279

0,51

16109,2

2,649

1,26

3602,2

4937,0

37

2,54

8,44

2,82

0,79

2,228

0,52

19483,4

2,764

1,34

3728,7

4789,7

38

2,69

8,89

2,87

0,76

2,178

0,54

22819,7

2,889

1,42

3862,6

4636,2

39

2,85

9,36

2,91

0,73

2,129

0,55

26095,6

3,026

1,51

4004,5

4475,4

40

3,03

9,85

2,96

0,70

2,079

0,57

29283,5

3,176

1,61

4155,4

4304,8

41

3,23

10,37

3,01

0,68

2,031

0,59

32356,1

3,340

1,71

4316,0

4127,6

42

3,45

10,92

3,05

0,65

1,983

0,61

35287,9

3,520

1,83

4487,4

3948,7

43

3,68

11,51

3,10

0,62

1,935

0,62

38054,0

3,718

1,96

4670,6

3771,2

44

3,93

12,12

3,14

0,60

1,887

0,64

40627,8

3,933

2,09

4866,3

3596,6

45

4,21

12,76

3,19

0,58

1,841

0,66

42982,1

4,168

2,24

5075,7

3427,4

46

4,50

13,45

3,23

0,56

1,795

0,67

45091,1

4,423

2,39

5299,6

3268,2

47

4,80

14,17

3,28

0,53

1,749

0,69

46931,3

4,699

2,56

5539,0

3124,5

48

5,12

14,92

3,32

0,51

1,704

0,70

48481,5

4,996

2,72

5794,6

3002,1

49

5,45

15,73

3,36

0,49

1,659

0,71

49722,0

5,313

2,89

6066,7

2905,8

50

5,78

16,57

3,40

0,47

1,615

0,72

50634,0

5,648

3,06

6355,8

2839,9

51

6,11

17,46

3,44

0,46

1,572

0,72

51198,9

6,001

3,22

6661,6

2808,7

52

6,43

18,40

3,48

0,44

1,529

0,72

51397,9

6,367

3,37

6983,7

2816,6

53

6,73

19,39

3,52

0,42

1,487

0,71

51211,3

6,743

3,51

7321,2

2867,5

54

6,99

20,44

3,56

0,41

1,445

0,70

50616,0

7,123

3,63

7672,5

2963,8

55

7,22

21,55

3,60

0,39

1,404

0,69

49582,9

7,500

3,72

8035,6

3106,1

56

7,39

22,71

3,64

0,38

1,364

0,67

48072,1

7,866

3,78

8407,8

3292,0

57

7,51

23,94

3,67

0,36

1,324

0,65

46029,8

8,215

3,81

8786,1

3517,0

58

7,56

25,24

3,71

0,35

1,285

0,62

43383,6

8,537

3,81

9167,3

3774,1

59

7,55

26,61

3,74

0,33

1,247

0,59

40038,9

8,825

3,77

9547,8

4055,0

60

7,47

28,05

3,77

0,32

1,209

0,56

35876,2

9,072

3,70

9924,4

4350,7

61

7,33

29,58

3,80

0,31

1,172

0,53

30750,8

9,274

3,60

10294,0

4654,3

62

7,14

31,19

3,83

0,30

1,136

0,50

24505,3

9,426

3,47

10653,9

4974,1

63

6,84

32,88

3,86

0,29

1,100

0,46

17037,6

9,525

3,27

11001,0

5387,6

64

6,20

34,67

3,88

0,27

1,064

0,38

8563,2

9,552

2,79

11327,8

6233,3

65

4,60

36,59

3,87

0,26

1,021

0,18

0,0

9,433

1,50

11606,3

8244,2

Source: elaborated by the author.

Figure 1 shows the dynamics of the stock of knowledge and the number of publications during the life cycle of the research professor. It is observed that although the professor accumulates knowledge during almost their whole life as a university professor, their academic production declines as from 58 years of age. This happens because, as it can be seen in the trajectory    in Figure 2, the fraction of time dedicated to research decreases as from 51 years of age, as a consequence of the reduction in the current value of the incentive to research. It can also be noted that the relation between the age of the professor and their publications is convex during the early years and becomes concave with time.

 

Figure 1. Dynamics of the stock of knowledge and publications

Source: elaborated by the author

If the starting salary increases to , the total production of a researcher during their life cycle increases to: , given that the average time fraction dedicated to research goes up, which now takes the value of   . The average final salary is . This means that this exogenous change in the salary allows the observation of the direct effect of the salary on intellectual output.

If added to the increase in the initial salary, the value of the salary point increases too, and VSP goes from 100 to 110, the total output of a researcher during their life cycle rises to , which is the result of the increase in the time fraction dedicated to research . Therefore, it can be concluded that the salary and the value of the salary point have a positive effect on the intellectual productivity of the representative professor of the model.

Figure 2 shows the graphs of the time fractions dedicated to research on the base line, and when there are exogenous changes in the salary and in the value of salary point. It is observed that as the salary and the value of the salary point increase exogenously, the fraction of time dedicated to research is higher for every year. In the two first cases, the highest peak of the fraction of time dedicated to research is reached at 51 years of age. The professor dedicates all their available time to research until they are 55 when the value of the salary point increases.

Figure 2. Time fraction dedicated to research in each simulation

Source: elaborated by the author

DATA

The aim of this section is to make a quick description of the data available for the estimation of the econometric model of the intellectual productivity of professors in public universities. The data corresponds to the information from the body of professors of the Universidad del Valle, for the period of 2004-2012.  The information includes: starting date at the university (year of recruitment), age, salary, faculty they belong to, academic level, category in the pay scale, research group they belong to, points for intellectual output, points for outstanding teaching practices, and points for academic-administrative managerial activities of the professors at the Universidad del Valle, subject to Decree 1279, which establishes the pay and tax scale of professors in state universities in Colombia.

Table 3 shows the average points for academic productivity per faculty, resulting from the annual salary update and its standard deviation. The highest average corresponds to the professors of the science faculty and the lowest is that of the school of psychology.

Table 3. Annual average of the points for productivity per faculty

Faculty

Obs.

Annual Average

Statistical Deviation

Binary Variation Representation

Arts

806

3,09

9,31

Administration

302

4,23

13,04

Engineering

1053

6,64

16,24

Socio-economics

176

5,65

12,29

Sciences

753

10,18

21,85

Psychology

145

2,91

8,63

Health

1158

3,44

11,22

Humanities

781

3,88

8,54

Source: elaborated by the author

Table 4 presents the average points for academic productivity per academic level and its standard variation. The professors with a doctorate show the highest productivity, followed by professors who hold a master’s degree (as was expected), that of the former being more than two and a half times higher than the latter. Professors with a specialization do not appear to have a research advantage over professors who hold a bachelor’s degree, as their degree of productivity is lower.

Table 4. Average annual points for academic productivity (per) academic level

Academic Level

Obs.

Annual average

Statistic deviation

Binary Variation Representation

Undergraduate

650

2,89

9,60

Specialization

925

1,98

6,86

Master’s Degree

2101

3,81

10,27

Doctorate

1498

10,10

20,83

Source: elaborated by the author

 

Table 5 presents the average points for academic productivity, according to the category of the professor and their standard deviation. It is observed that the average points for academic productivity of the professors’ increases in accordance with the academic degree reached.

Table 5. Average annual points for intellectual productivity according to category

Category

Obs.

Annual Average

Statistical deviation

Representation

Binary Variation

Auxiliary

921

2,20

5,85

Assistant

1629

4,21

12,00

Associate

909

5,65

13,09

Tenure

1715

7,49

18,50

Source: elaborated by the author

Table 6 displays the descriptive statistics of the average of the age of the professors, the real salary at 2007 prices, and the points accumulated for outstanding teaching practices and academic productivity during the years 2004-2011.

Table 6. Descriptive statistics of the continuous variables

Variable

Obs.

Annual Average

Statistic deviation

Min.

Max.

Representation

Age

6059

48,7

8,6

25

84

Real salary

6059

3’526.821

1’763.153

824.942

15’100.000

Points for outstanding teaching practices

6059

7,9

8,7

0,0

50,0

Points for intellectual productivity

6059

91,5

135,9

0,0

1350,9

Source: elaborated by the author

ESTIMATION OF THE ECONOMETRIC MODEL AND ANALYSIS OF THE RESULTS

The specification of the econometric model for intellectual output is the following:

Where:

 points for intellectual output of the professor  in the period .

: is equivalent to the current net value of the profit expected from each point of intellectual productivity in the period   .

: real salary of a professor  in the period , the period in which the professor starts the research that leads to a publication in the following period.

The vector  contains information about other variables that may have influence on intellectual productivity such as the highest academic degree of the professor, the area of science they belong to (Faculty or institution), research group they belong to, seniority, points for intellectual output, category in the pay scale, etc.

The expression for the calculation of the  variable is the following:

In (9), the term VSP corresponds to the value of the salary point, NAP is the number of annual payments that the professor receives, and  is the discount rate that is established exogenously. The values assigned are: VSP =  and NAP = 15.

The specification of the model (8) proposes a relation between real salaries and intellectual productivity which has the shape of an inverted U and follows Tang (2000). The reason that the author suggests is the following: to begin with, the initial increase in the salaries of the employees makes them more productive, because said increase makes leisure more expensive. Nevertheless, the additional increase in the salaries will reduce productivity, because the employees get richer and allow themselves more free time.

So as to have a first approximation of the factors that determine professors’ publications, a Logit model is estimated where the dependent variable is the binary variable . The variable takes a value of one if the professor had a salary update in that period[3], which gave them points for intellectual productivity, and zero if it is not the case.

 The estimation of the Logit model appears in Table 7. The age, salary, points for intellectual productivity and outstanding teaching practices are left aside, in order to take into account the moment in which the decision was made to do research with the aim of publishing the article or book of interest. The variables of the professors’ pay scale category, the real salary lagged in levels, and the binary variables of the faculties are not significant, except for the humanities and psychology dummies.

Table 7. Logit model of random effects to establish the determinants of publication

Binary Dependent Variable

 

Observations

2509

Number of groups

771

 

 

Explanatory variable

Coefficient

Standard error

0.1492

0.1888

0.79

0.430

0,4376

0.2570

1.70

0.089

-0.0582

0.3229

-0.18

0.857

0.4956

0.2340

2.12

0.034

0.6836

0.2122

3.24

0.001

1.3992

0.2467

5.67

0.000

0.8850

0.1417

6.24

0.000

-0.050

0.0095

-5.27

0.000

-5.07e-09

1.67e-07

-0.03

0.976

-6.63e-14

1.82e-14

-3.64

0.000

0.0126

0.0016

7.85

0.000

0.0216

0.0088

2.45

0.014

0.7764

0.2162

3.59

0.000

-0.7529

0.4008

-1.88

0.060

-0.0140

0.2114

-0.07

0.947

0.2115

0.3480

061

0.543

-0.1143

0.2930

-0.39

0.696

0.3244

0.2113

1.53

0.125

0.0287

0.2476

0.12

0.908

0.3023

0.1503

2.01

0.044

0.2590

0.1562

1.66

0.097

0.5817

0.1710

3.40

0.001

Source: elaborated by the author

Table 8 presents, in columns (II) and (III), the estimation of the life cycle and intellectual output models, through a Tobit estimation of random effects. The only difference between the models is that the first uses age as a regressor, and the second uses the incentive for intellectual output as an explanatory variable of interest.

On the other hand, there can be some bias in the estimators of the Tobit model of random effects if the non-observed individual heterogeneity has the shape of fix/steady effects correlated with the explanatory variables. In order to overcome this problem, Levin and Stephan (1991) estimate a Tobit model which includes individual dummies, Goodwin & Sauer (1995) and Rauber & Ursprung (2008) incorporate a categorical variable, the result of ranking researchers in quintiles from the average production of their life cycle. Following a similar strategy, Vella and Verbeck (1997) use the residuals of a preliminary regression to rank researchers based on their research ability, not captured by the deterministic part of the model. In columns (IV) and (V), the estimations of the life cycle and intellectual output models appear, using the Vella and Verbeck (1997) methodology to capture the fixed individual heterogeneity.

The discount rates used in the models of intellectual output were:  (there is no discount rate) in the Tobit model of random effects and  for the Tobit model that follows the methodology of Vella and Verbeck (1997).

As was to be expected, the more the academic level of the professor increases, the more their intellectual output improves. The estimations show that a professor with a doctorate has approximately 6 points more for intellectual output than a professor who holds a master’s degree, and almost 8 points more than a professor with a specialization.

Being part of a research group has a positive effect on intellectual output of approximately 6 points a year.

The effect of age is negative, because the older the professor gets, the profit expected from publications drops. Even when with the passing of time the research professor improves their stock of knowledge and, therefore, their publishing abilities, this positive effect is captured by the following variables: lagging accumulated intellectual productivity ( ) and points for lagging accumulated outstanding teaching practice ), so a quadratic form is not required for age.

 

The effect of the incentive is positive and significant. The idea of including the variables ( ) and  is that the incentive effect does not include other effects associated with age. In fact, if this pair of variables is not included, age and age squared are significant, with their respective positive and negative signs. For this reason, if variables 

( ) and were not included as regressors, the effect of the incentive would be underestimated.

It is also important to highlight that, despite the incorporation of the average production of a professor during their life cycle (residual) as an explanatory variable of the Tobit model, the variable ( ) remains significant, which shows that the individual contributions of these two variables to the model are essential. The residual variable is also significant.

The Faculty of Science features ceteris paribus, the greatest intellectual output, which would be nearly 3 points above the average of the university. In the Tobit estimation of random effects, the lowest ceteris paribus intellectual output is found in the Institute of Psychology. In Vella and Verbeck’s (1997) Tobit estimation, the School of Science produces the lowest ceteris paribus intellectual output.

The variable lagging real salary in levels is not significant in any of the estimations, and the same variable squared turned out to be significant (only in the Tobit estimation of random effects) as well as its negative effect, because when a professor receives a high salary, they prefer leisure over income or status in the university.

Binary period variables are included to capture the cohort effect following the recommendation of Rauber and Ursprung (2005). The time dummies reveal the rapid growth in the intellectual output of the Universidad del Valle professors, not associated with the individual characteristics observed.

Table 8. Estimation of life cycle and intellectual output models

Dependent variable

Points for intellectual output ( )

Number of observations

2509

Explanatory variable

Tobit estimation of                                                   random effects

Tobit estimation – Vella and Verbeck methodology (1997)

Life cycle Model (II)

Intellectual output

(III)

Life cycle Model (IV)

Intellectual output

(V)

3.1452

3.1230

3.0889

3.0739

0.077

0.088

0.049

0.050

6.1391

6.1207

4.9007

4.9032

0.000

0.000

0.000

0.000

12.6735

12.6659

10.9312

10.9147

0.000

0.000

0.000

0.000

6.1416

6.1376

5.8459

5.8402

0.000

0.000

0.000

0.000

-0.5108

-

-0.5333

-

0.000

0.000

-

3.16e-6

-

3.44e-6

0.000

0.000

-6.03e-13

-6.04e-13

-

-

0.000

0.000

0.1285

0.1286

0.0576

0.0576

0.000

0.000

0.000

0.000

0.1475

0.1475

0.0962

0.0959

0.019

0.020

0.071

0.072

-

-

1.1096

1.1096

0.000

0.000

3.261

3.2567

2.7849

2.7754

0.011

0.012

0.006

0.007

-

-

-2.5572

-2.5540

0.027

0.027

-5.6811

-5.6844

-

-

0.060

0.060

2.9069

2.9276

2.0193

2.0251

0.013

0.014

0.072

0.071

3.9471

3.9617

3.3067

3.3147

0.001

0.001

0.004

0.003

8.1645

8.1932

6.3004

6.3135

0.000

0.000

0.000

0.000

Source: elaborated by the author

The estimated effects of the incentive for intellectual output were

for the Tobit model of random effects and  in the Tobit model that follows the methodology of Vella and Verbeck (1997). The latter is approximately 8.8% higher than the Tobit model with random effects, but it must be taken into consideration that, in the Tobit estimation of random effects to the incentive, discount rates are not applied.

Figures 3 and 4 show the estimated effect of the incentive ceteris paribus, over the intellectual productivity of the professors of the Universidad del Valle, calculated from the random effects Tobit model (Figure 3) and the Vella and Verbeck Tobit model (Figure 4). In the first, the effect is 20.3 points for a 30-year-old professor, 15.27 points for a 40-year-old, 10.18 for a 50-year-old, and 5 points for a 60-year-old. In the second the effect is 15.4 points for a 30-year-old professor, 12.59 points for a 40-year-old, 9.15 points for a 50-year-old, and almost 5 points for a 60-year-old professor.

Figure 3. Estimated effect of the incentive over intellectual output calculated based on the random effects Tobit estimation.

Source: elaborated by the author

Figure 4. Estimated effect of the incentive over intellectual output calculated based on the Vella and Verbeck Tobit estimation (1997).

Source: elaborated by the author

Figure 5 reveals the estimated effects using the results of the Tobit model with fix effects of increments of 10 %, 20 %, 30 %, 40 % and 50 % in the value of the salary point over intellectual output, associated with each age level.

effect

effect

effect

effect

Figure 5. Estimated effect of the percentage increase of the salary point value

Source: elaborated by the author

 

CONCLUSIONS

 

In the year 2012, out of 759 professors covered by Decree 1279, 23.8% were professors without a Master’s degree or a doctorate, 44.3% were professors with Master’s degree, and 31.8% had a doctorate. The estimations found that a professor with a doctorate has approximately 6 more points for intellectual output than a professor who only holds a Master’s degree, and almost 8 more points than a professor who only has a specialization. The first difference is equivalent to the publication of a couple of C type articles a year and the second to one B type article a year. Therefore, there exists the possibility to increase intellectual output, through the policy of study commissions to improve the academic level of professors.

 It was discovered that participation in a research group affects intellectual output by almost 6 points, a similar contribution to the difference in intellectual output between a professor with a doctorate and one with a Master’s degree. For this reason, it is important that the authorities foster professorial participation in research groups.

In the theoretical model developed in this article, the salary of a professor affects their intellectual output, because the higher their salary in the public university, the less time the professor dedicates to other activities that generate income, such as, for example, working at another university or consulting. Nevertheless, the empirical evidence obtained from the estimations reveals that the level of salary does not have a positive effect on the intellectual output of professors in public universities. This can be considered an indicator that there is no tradeoff between the time dedicated to research and that dedicated to other activities that generate income.

In the article of Levin and Stephan (1991), the salary of a professor turned out to be significant in the explanation of their research productivity, but it has to be highlighted that, in that estimation, salary was used as a proxy of the future profits of the professor’s publications. In this article, there is an approximate measurement of the marginal utility of the research (the current value of the salary point).

However, given that the estimation sample covers only professors from the Universidad del Valle, a public university with relatively low starting salaries, the effect of the salary in hiring teachers with better research abilities cannot be determined and, therefore, it's effect on intellectual output cannot be determined either. Due to this limitation, what can be observed is that the salary level does not affect intellectual output through the distribution of time dedicated to research.

The estimations found an average effect of the salary incentive over productivity of 15.4 points for a 30-year-old professor, 12.59 points for a 40-year-old professor, 9.15 points for a 60-year-old professor, and almost 5 points for a 60-year-old professor, etc. What is clearly revealed is the importance of the incentive factor, if we compare it with the difference estimated for the effect on intellectual output, between having a doctorate and a master's degree which provides around 6 points, or being part of a research group which provides 6 points.

The best estimation in the Tobit model of Vella and Verbeck (1997) was obtained with a 1.9% discount rate, and in the Tobit estimation with random effects without discount rate. Given the low magnitude of the discount rate, it can be concluded that the strategy of some private universities of offering premiums for intellectual output over a limited period (a year) does not compete with the incentive of the public university, because a very high amount of the marginal value of the premium for intellectual output would be required, in order to balance the time during which the professors of public universities receive their compensation, especially in the case of young professors.

One of the main problems that public universities in Colombia face when hiring new professors is the legal restrictions in setting a starting salary that can attract the most talented candidates in the market[4]. However, teaching in a Colombian public university also has a couple of aspects in its favor: i. Exclusive dedication is not required, ii. Depending on labor seniority, experience, and, above all, their publications, a professor in a public university may get to earn the same as or more than a professor in a private university.

If the advantages that a public university offers compensate the low starting salary of the professors of public universities, the distribution of research abilities of the professors hired would not be affected, and in that case, it could be affirmed that the salary incentive policy is preferred to that of high salaries.

In this sense, policies such as the position of full time professor may positively affect research, because it may help to reduce the starting salary restriction which enables the hiring of professors with greater research abilities, as it allows the salary of the professor to increase by up to 22%. However, a direct effect of the highest salary on effort in research and intellectual output would not be expected.

The significance and the effect of the time dummies also showed the ceteris paribus growth of the intellectual output of the professors in the Universidad de Valle, probably due to cohort effects and a greater opportunity to publish, associated with a better supply of specialized journals or journals better ranked by Colciencias, or both.

 

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* This article is part of the thesis “Salaries and Work Productivity in Colombia” to opt for the title of the Doctorate in Development Economics of the Latin American Faculty of Social Sciences, Ecuador branch.

 

** Assistant professor, Economics Department, Universidad del Valle, Cali, Colombia. Civil Engineer from the Universidad Francisco de Paula Santander. Master’s Degree in Economics from the Universidad Javeriana. Master’s Degree in Environmental Economics and Natural Resources from the Universidad de los Andes. Jhon.mendez@correounivalle.edu.co

 

 

*** Associate Professor. School of Economics, Universidad  Central de Venezuela, Caracas, Venezuela. Ph.D. University of London, England. leoverave@gmail.com

[1] In the year 2014, the average starting salary of a professor who holds a doctorate was only 3.8 million Colombian pesos on average.

 

[2] In the simulation, it is assumed that each publication corresponds to a salary point, in fact each publication is valued on the basis of article 10 of Decree 1279.

 

[3] Each period corresponds to two years, assuming cycles of research-publication every couple of years.

 

[4]In the year 2014, the average starting salary of a professor with a doctorate was only 3.8 million pesos a year, on average.