اشتغال و یا خود اشتغالی: یک مدل حداکثر کردن ابزار پویا

This article presents a dynamic utility-maximizing model of career choice between self-employment and employment that takes into consideration the differences among people in terms of their initial attitudes toward job attributes and the likely changes to those attitudes as they mature. These differences between people affect the choice of career that maximizes their utility (there are at least five optimal career paths). This dynamic utility-maximizing model helps increase our understanding not only of why some people become self-employed but also of why and when some self-employed people switch to employment.

Stevenson and Jarillo (1990) propose that entrepreneurship research can be classified into how entrepreneurs act (i.e., what it is they do), what happens when entrepreneurs act (i.e., what are the outcomes of their actions), and why people choose to act as entrepreneurs (i.e., what motivates them). Economic theory has been used in the entrepreneurship domain primarily to investigate what happens when entrepreneurs act and how they do it Herbert and Link, 1988 and Barreto, 1989 — the first two classifications of entrepreneurship research. While there is a considerable literature on career choice from a variety of disciplines (e.g., labor economists, organizational behaviorists, and sociologists), the focus has been almost exclusively on job mobility patterns within and across established firms Borjas, 1986 and Carroll and Mosakowski, 1987. Only recently have scholars turned their attention toward an economic perspective on why people choose self-employment. Baumol (1990) suggests that people are motivated by the reward structure in the economy — the rules of the game that govern the payoff. Campbell (1992) proposes that the payoff can be evaluated using an expected net present value (ENPV) and that a person will be motivated to be an entrepreneur when the ENPV of profit from entrepreneurship is positive (profit includes a monetary evaluation of psychic costs and benefits). Eisenhauer's (1995) economic model of the decision to be an entrepreneur is based on the expected utility derived from income and the working conditions of employment vs. self-employment. Douglas and Shepherd (2000) represent an individual's choice to be self-employed by a utility-maximizing model where people intend to be self-employed when the combination of income, risk, work effort required, and independence provides greater utility than does the corresponding combination for the best employment option. People differ in what gives them utility, and this explains why some people intend to be self-employed while others intend to be employed. Scholars modeling the intention to be self-employed, by necessity, have held a number of variables constant in order to study only those parts of the decision under investigation. In a previous study, two of the present authors assumed that a person's attitudes do not change over time and therefore an intention to be self-employed (or employed) is relatively stable (Douglas and Shepherd, 2000). But, of course, this assumption may not always hold, and changes in attitudes could significantly affect the intention to be self-employed and consequently the career path that a person may follow over his/her lifetime. For example, studies based on life cycle and career stage models have indicated that determinants of job attitudes change (Lee and Wilbur, 1985). Accordingly, we propose that a person's intention to be self-employed may change over time. There is empirical evidence suggesting that age affects the movement to and from self-employment (e.g., Quinn, 1980, Fuchs, 1982 and Rees and Shah, 1986), but the nature of this relationship is unclear. For example, some scholars argue that there is a strong positive relationship between age and self-employment (e.g., Quinn, 1980). Some scholars suggest that the probability of self-employment increases with age and then remains constant from the early forties until the retirement years (Evans and Leighton, 1989), and others find that the probability of self-employment is convex with age Brock and Evans, 1986 and Borjas, 1987.3 This discussion leads to our research question: What effects do age-related changes in attitudes have on a person's choice between being self-employed and employed? In addressing this question, the present article makes a number of small but important contributions to the entrepreneurship and career literatures. First, previous research into why people choose self-employment has relied on the assumption that entrepreneurship is associated with a stable set of individual characteristics (Carroll and Mosakowski, 1987) including attitudes (e.g., Douglas and Shepherd, 2000). In this article, we use a deterministic discrete-time mathematical formulation to investigate career intentions (to be self-employed or employed) over time. Mathematical models have already been used to investigate career paths, and while this approach has its own limitations, it does not assume temporal equilibrium.4 Therefore, we not only can address the question of why some people choose self-employment over employment but also investigate why a person may change in and out of self-employment and when these changes might occur. Second, previous researches studying career choice and age have considered people as a homogeneous group, and their results have been inconclusive. In contrast, we propose that groups of people differ not only in their abilities and attitudes but also in how these abilities and attitudes change over time. We propose that these differences are important in understanding lifetime career paths. This study proceeds as follows: First, we review an economic perspective on entrepreneurship as a utility-maximizing response. Second, we supplement this static perspective on career choice with knowledge (and assumptions) about the way people's attitudes typically change over time. This discussion leads to a number of assumptions that will be used in the formulation of our dynamic model of career choice. Third, we formulate the dynamic model and describe optimal career paths. We present a sensitivity analysis for key parameters. Finally, we suggest some implications of this study for scholars and practitioners.

By leveraging the standard utility-maximizing approach, the model presented here provides a tool to analyze the possibility of people switching between employment and self-employment as they age and to suggest under what conditions this may happen. Specifically, we learn from the model that boundary conditions on the utility of self-employment over employment (coefficients a, b, and c and their summation) may help explain career path selections. Different individuals experience different changes over time in their ability as well as in their attitudes toward income, work effort, risk, and independence, and these may alter a career path. Nevertheless, we believe that a career path is not predetermined — utility weights can be changed by factors other than age. Attitudes can be learned; therefore, those entities trying to encourage people to be self-employed would be well advised to understand not only how utility weights change over time but also how education and other environmental factors can mold attitudes. A number of other research opportunities arises from the model presented in this article. First, to become self-employed, people need not only the appropriate utility weights but also opportunity and resources. Future research might consider, for example, that one aspect of ability could be opportunity recognition, and as we mature, our ability to perceive opportunities might increases, changing our potential career paths. Second, it is not always the case that income is higher for self-employment than for employment; some self-employment opportunities (e.g., lifestyle businesses) may produce lower income than employment. Under such circumstances, the “marginal utility” parabola becomes positive and is flipped over, offering a different perspective on optimal career paths. Finally, there is also an opportunity to test this dynamic model empirically. There are already well-established surveys for capturing attitudes and intentions (e.g., Cable and Judge, 1996). Such research could build on this model and further increase our understanding of how utility weights change over time and how these changes influence which career we choose and when. This represents an important research agenda for entrepreneurship and career scholars.