The Timing of Capacity Investment with Lead Times: When Do Firms Act in Unison?

We study competitive capacity investment for the emergence of a new market. Firms may invest either in capacity leading demand or in capacity lagging demand at different costs. We show how the lead time and other operational factors including volume flexibility, existing capacity, and demand uncertainty impact equilibrium outcomes. Our results indicate that a type of bandwagon behavior is the most likely equilibrium outcome: if both firms are going to invest, then they are most likely to act in unison. Contrary to much received wisdom, we show that leader–follower behavior is very uncommon in equilibrium where firms do not have volume flexibility, and will not occur at all if lead times are sufficiently short. On the other hand, if there is volume flexibility in production, then the likelihood of this sequential investment behavior increases. Our findings underscore the importance of operational characteristics in determining the competitive dynamics of capacity investment timing.     

A critique of the ZPG urban stress test: On the uses and misuses of social indicators

This is an expanded version of a paper originally prepared for presentation at the annual meetings of the North Central Sociological Association: Louisville, KY; March 22–24, 1990.     

Social indicators in policy planning: Applying the public marketing model in Yuba city,California

This article is a follow up to a paper appearing in the Spring Issue (4) 1977 of this Journal by the same authors entitled ‘Public Marketing: A Suggested Policy Paradigm for Community Development in the City’. In the earlier article a public marketing model was advanced as a device to order socioeconomic needs for planning and policy making in city government. This article provides an empirical application of the model in an actual city. The results indicate that the model is a workable and useful tool for social indicator construction and policy formulation.     

Population Redistribution And Changes In The Size Density Slope

As regional population density increases territorial units tend to subdivide. For maximum societal time-efficiency the slope relating the logarithms of unit areas to those of unit densities should be -2/3. When boundaries become fixed, however, observed slopes tend to drift toward a value of zero. It was earlier hypothesized that such slope-erosion was due to increasing concentration of the population. Historical data for the primary political divisions of ten nations shows general support for the hypothesis.     

Exchange and cohesion in dyads and triads: A test of Simmel’s hypothesis

This paper uses social exchange theory to address a classic question posed by Simmel (1964) regarding dyads and triads. The question is whether exchanges in a triad will generate more cohesion at the group level than exchanges in an isolated dyad. The main hypotheses, integrating several ideas from Simmel and social exchange theories, are as follows. First, triads generate less variability of behavior than dyads; that is, there is more uniformity or convergence in triads. Second, in the context of repeated exchange, we predict higher levels of cohesion in triads than in dyads. Third, positive emotion or affect has a stronger impact on cohesion in dyads than in triads, whereas uncertainty reduction has a stronger impact on cohesion in triads. To test these hypotheses, an experiment compared isolated dyads to dyads nested in a triadic exchange network. Subjects engaged in exchanges across a series of distinct episodes, using standard experimental procedures from research on relational cohesion (Lawler and Yoon, 1996) and exchange networks (Molm and Cook, 1995, Willer, 1999). Consistent with the hypotheses, the results reveal more convergence of behavior and higher cohesion in triads than in dyads; moreover, uncertainty reduction is the primary basis for cohesion in the triad, whereas positive affect was the primary basis for cohesion in the dyad. These results are discussed in relation to Simmelian dyad–triad dynamics and the theory of relational cohesion.     

Rates of missing responses in personal digital assistant (PDA) versus paper assessments

This article describes rates of missing item responses in personal digital assistant (PDA) assessments as compared to paper assessments. Data come from the evaluation of a classroom-based leisure, life skills, and sexuality education program delivered to high school students in Cape Town, South Africa. Analyses show that the paper assessments had much higher rates of missing-ness than PDA assessments. This association is moderated by item order. Certain analyses also suggest that paper assessments have higher rates of missingness for items pertaining to participants' sexual behavior. Implications of these results for evaluation research will be discussed.     

Sleep and behavioral correlates of napping among young adults: a survey of first-year university students in Madrid, Spain

Objective: Between November 2002 and March 2003, the authors assessed the prevalence and correlates of napping among Spanish university students. Participants: The sample comprised 1,276 first-year university students; the mean age was 18.74 +/- 1.24 years, and 35.45% were men. Methods: The study was cross-sectional, and the students completed self-report, anonymous questionnaires provided during an in-class survey. Results: Almost half (44%) of the sample reported napping (90% did so after lunch for longer than 1 hour). Multiple logistic regression analysis showed that experiencing an irregular sleep-wakefulness pattern, having a morning school schedule, and being male were significant predictor variables of napping. Further significant outcome variables related to napping were having excessive daytime sleepiness, missing classes because of tiredness, better ability to concentrate later in the afternoon, and a perception of deeper nighttime sleep. Conclusions: Habitual napping is common among Spanish university students and associated with an irregular sleep-wakefulness pattern. Taking long postlunch naps seems to be used by students to cope with insufficient sleep and daytime sleepiness.