OPTIMAL BUFFER ALLOCATION IN ASYNCHRONOUS CYCLIC MIXED-MODEL ASSEMBLY LINES

This paper considers a problem of optimal buffer allocation in cyclic asynchronous mixedmodel assembly lines with deterministic processing times. An analytical model is used to provide new insights into properties of optimal buffer allocation, that is, a buffer configuration that guarantees the highest possible throughput rate on the assembly line with a minimum number of buffers. Optimal buffer configuration is characterized, and an efficient algorithm to find such a configuration is developed. The approach proposed in this paper also provides insights on how to allocate a given number of buffers to workstations on the assembly line to maximize the throughput rate.     

THE EFFECT OF LEARNING ON THE MAKE/BUY DECISION

By including the effects of learning over time on both the production of components and their integration into complete products, we develop an engineering‐based model of outsourcing. This model provides an alternative explanation for much of what other outsourcing theories predict, as well as making several new predictions. In particular, we show that outsourcing decisions can create a path‐dependent outsourcing trap in which a firm experiences higher long‐run costs after an immediate cost benefit. We also describe conditions under which outsourcing a small fraction of component production may dominate either complete insourcing or complete outsourcing. Finally, we show that, with discounting, there is a convex, curvilinear relationship between the optimal outsourcing fraction and the rate of technological change.     

PERFORMANCE ANALYSIS OF AN ASSEMBLY STATION WITH INPUT FROM MULTIPLE FABRICATION LINES

We develop analytical models for performance evaluation of Fabrication/Assembly (F/A) systems. We consider an F/A system that consists of an assembly station with input from K fabrication lines. Each fabrication line consists of one or more fabrication stations. The system is closed with a fixed number of items circulating between each fabrication line and the assembly station. We present algorithms to estimate the throughput and mean queue lengths of such systems with exponential processing times. We then extend our approach to analyze F/A systems with general processing time distributions. Numerical comparisons with simulations demonstrate the accuracy of our approach.     

ANALYSIS OF THE LEAD TIME AND LEARNING FOR CAPACITY EXPANSIONS

Firms capable of reducing the time required to bring new products to the marketplace realize significant competitive gains. In this context, the existing literature on capacity expansion is limited because it does not consider the lead time required to construct and operationalize new capacity. Models are introduced here that capture the capacity expansion lead time as well as two types of learning. Specifically, learning may reduce the lead time or cost required to complete an expansion. Analytic and numerical results show that the optimal solution can be significantly affected by the explicit treatment of the lead time and learning.     

THE USE OF INDUSTRIAL SOFTWARE TO CREATE EXPERIENTIAL LEARNING ACTIVITIES IN OPERATIONS MANAGEMENT COURSES

Computer-based manufacturing planning and control (MPC) systems are widely used in industry to gain competitive advantage through integration and coordination of managerial activities. In collegiate business schools, important operations management activities are taught and studied, often by sequential examination of discrete topics such as aggregate production planning, master production scheduling, capacity planning, material planning, and production activity control. This paper explores the potential use of industrial MPC software in the classroom to create experiential learning activities that address the dynamic and integrative nature of operations management. Experiences with this pedagogical approach over the past decade are reported.     

THE DEPENDENCE OF THE EFFECTS OF LEARNING MODE ON CONCOMITANT FACTORS*

Despite the number of studies comparing the programmed instruction (PI) and text teaching methods, the results to date have been inconclusive. In this paper it is hypothesized that the effects of these two modes of learning on performance are dependent on differences in people and in the material to be learned. In an experiment on 48 subjects it was found that both mode of learning and sex affected performance, but the effect of sex differed for the two modes of learning. Women performed better in the PI mode and men performed better in the text mode. Also, performance on definitional material was dependent on the aptitude of the learner and on inferential material was dependent on the prior knowledge of the learner.     

THE EFFECT OF BENEFIT SANCTIONS ON THE DURATION OF UNEMPLOYMENT

This paper investigates the effectiveness of unemployment benefit sanctions in reducing unemployment duration. Swiss data on benefit sanctions allow us to separate the effect of a warning that a person is not complying with eligibility requirements from the effect of the actual enforcement of a benefit sanction. Moreover, public employment services are given substantial leeway in setting the monitoring intensity. Results indicate that both warning and enforcement have a positive effect on the exit rate out of unemployment, and that increasing the monitoring intensity reduces the duration of unemployment of the nonsanctioned. (JEL: J64, J65, J68)     

RETHINKING THE EFFECT OF IMMIGRATION ON WAGES

This paper calculates the effects of immigration on the wages of native US workers of various skill levels in two steps. In the first step we use labor demand functions to estimate the elasticity of substitution across different groups of workers. Second, we use the underlying production structure and the estimated elasticities to calculate the total wage effects of immigration in the long run. We emphasize that a production function framework is needed to combine own‐group effects with cross‐group effects in order to obtain the total wage effects for each native group. In order to obtain a parsimonious representation of elasticities that can be estimated with available data, we adopt alternative nested‐CES models and let the data select the preferred specification. New to this paper is the estimate of the substitutability between natives and immigrants of similar education and experience levels. In the data‐preferred model, there is a small but significant degree of imperfect substitutability between natives and immigrants which, when combined with the other estimated elasticities, implies that in the period from 1990 to 2006 immigration had a small effect on the wages of native workers with no high school degree (between 0.6% and +1.7%). It also had a small positive effect on average native wages (+0.6%) and a substantial negative effect (−6.7%) on wages of previous immigrants in the long run.     

THE EFFECT OF JOINT CUSTODY ON FAMILY OUTCOMES

Since the 1970s almost all US states have introduced a form of joint custody after divorce. I analyze the causal effect of these custody law reforms on different family outcomes. My identification strategy exploits the different timing of reforms across the US states. Estimations based on state panel data suggest that the introduction of joint custody led to an increase in marriage rates, an increase in overall fertility (including a shift from nonmarital to marital fertility), and an increase in divorce rates for older couples. Accordingly, female labor market participation decreased. Further, male suicide rates and domestic violence fell in treated states. The empirical evidence is consistent with the hypothesis that joint custody increased the relative bargaining power of men within marriage.     

THE EFFECT OF RETAIL PROMOTIONAL ACTIVITIES ON SALES*

This article reports the formulation and results of a multiple equation econometric model to relate retail sales by brand and package size to retail promotional variables for a branded, frequently purchased grocery product. Primary emphasis is placed on the formulation of the model as opposed to the results obtained from its use.     

A LONGITUDINAL STUDY OF THE EFFECT OF A SERVICE GUARANTEE ON SERVICE QUALITY

This paper develops a theoretical framework that relates a service guarantee to service quality. The framework hypothesizes that a service guarantee can positively affect service quality through its positive effect on both learning through service failure and employee motivation and vision. A longitudinal, empirical study was conducted to test these hypotheses. Surprisingly, the service guarantee was not found to have a direct effect on learning through service failure. However, the service guarantee clearly had a positive effect on service quality primarily through its positive effect on employee motivation and vision. The research strongly supports using a service guarantee to improve service quality.     

THE EFFECT OF MASCULINE AND FEMININE BRAND NAMES ON THE PERCEIVED TASTE OF A CIGARETTE *

The purpose of the current study was to determine whether brand name can affect the public's evaluation of a product. All subjects smoked identical cigarettes. One group of subjects, however, knew the cigarettes by the name of “Frontiersman,” a masculine name, while the other group knew the cigarettes as “April,” a feminine name. Male and female subjects were asked to rate the cigarette on seven measures. Results show that women gave a more positive evaluation to the cigarette purportedly named “April,” while men gave a more positive evaluation to the identical cigarette when they thought it was named “Frontiersman.” In addition, women reacted more strongly than did men to brand name influence.     

SOCIAL LEARNING THEORY AND THE IMPLEMENTATION OF PRODUCTION INNOVATION*

In a study of the implementation of production innovation using a social learning theory focus, four organizations were monitored with a real-time study design. The following propositions were strongly supported: (1) During the initial implementation period (3–4 months), the stress felt by personnel in new user organizations was significantly higher (p < .01) than for organizations previously experienced with technology; (2) Firms experienced with the new technology obtain early success when compared with inexperienced firms (p < .01). Moderate support was found for the proposition that new users rely heavily on original equipment manufacturers for demonstration to acquire new skills, but gradually models within the user organization emerge as the dominant influence. The proposition that new users have significantly higher imitation scores than users experienced with the technology was only weakly supported. No substantive or significant changes in the attitudes of users toward the innovation were found during the first three to four months of the implementation period. These and other results suggest that longitudinal studies of this type ought to be carried out over periods in excess of 2 1/2 years. Implications for the management of change are presented.     

THE EFFECT OF FINANCIAL REWARDS ON STUDENTS' ACHIEVEMENT: EVIDENCE FROM A RANDOMIZED EXPERIMENT4

This paper reports on a randomized field experiment in which first‐year university students could earn financial rewards for passing all first‐year requirements within one year. Financial incentives turn out to have positive effects on achievement of high‐ability students, whereas they have a negative impact on achievement of low‐ability students. After three years these effects have increased, suggesting dynamic spillovers. The negative effects for less‐able students are consistent with results from psychology and behavioral economics showing that external rewards may be detrimental for intrinsic motivation. (JEL: I21, I22, J24)     

CHILDREN OF A (POLICY) REVOLUTION: THE INTRODUCTION OF UNIVERSAL CHILD CARE AND ITS EFFECT ON FERTILITY

What role does affordable and widely available public child care play for fertility? We exploit a major German reform generating large temporal and spatial variation in child care coverage for children under the age of three. Our precise and robust estimates on birth register data reveal that increases in public child care have significant positive effects on fertility. The fertility effects are more pronounced at the intensive than at the extensive margin, and are not driven by changes in the timing of births or selective migration. Our findings inform policy makers concerned about low fertility by suggesting that universal early child care holds the promise of being an effective means of increasing birth rates.     

THE EFFECT OF CENTRAL EXIT EXAMINATIONS ON STUDENT ACHIEVEMENT: QUASI‐EXPERIMENTAL EVIDENCE FROM TIMSS GERMANY

This paper makes use of the regional variation in schooling legislation within the German secondary education system to estimate the causal effect of central exit examinations on student performance. We propose a difference‐in‐differences framework that exploits the quasi‐experimental nature of the German TIMSS middle school sample and discuss its identifying assumptions. The estimates show that students in federal states with central exit examinations clearly outperform students in federal states without such examinations. However, only part of this difference can be attributed to the existence of the central exit examinations themselves. Our results suggest that central examinations increase student achievement by the equivalent of about one‐third of a school year. (JEL: D02, H42, I28)     

ON THE THEORY OF ETHNIC CONFLICT

When considering engaging in conflict to secure control of a resource, a group needs to predict the amount of post‐conflict leakage due to infiltration by members of losing groups. We use this insight to explain why conflict often takes place along ethnic lines, why some ethnic groups are more often in conflict than others (and some never are), and why the same groups are sometimes in conflict and sometimes at peace. In our theory ethnic markers help enforce group membership: in homogeneous societies members of the losing group can more easily pass themselves as members of the winning group, and this reduces the chances of conflict as an equilibrium outcome. We derive a number of implications of the model relating social, political, and economic indicators such as the incidence of conflict, the distance between ethnic groups, group sizes, income inequality, and expropriable resources. One of the insights is that the incidence of ethnic conflict is nonmonotonic in expropriable resources as a fraction of total resources, with a low incidence for either low or high values. We use the model’s predictions to interpret historical examples of conflict associated with skin pigmentation, body size, language, and religion.