Competitive strategies in retailing

A strategy formulation procedure for retailers is described. The changing retail environment has brought problems for some traditional forms of retailing, and indeed failure for some stores, but it has also brought opportunities, particularly for the store management that has been prepared to consider different ways of selling.     

Measuring the Cost of the Fear of Unemployment: An Information Approach

A method of measuring the insecurity costs of unemployment or what might be termed the fear of unemployment effect is proposed. The approach is from an individual perspective and builds on a cost measure first suggested by Lucas. The measure is designed to abstract away from any output losses that might be incurred in a recession. The latter is the traditional Keynesian way of measuring recession costs. The paper demonstrates the intuitively sensible properties of the measure and argues that to neglect the fear of unemployment effect as is done with standard Keynesian cost measures could seriously underestimate recession costs for some individual types. The paper concludes with a multiperiod simulation of the insecurity cost measure.     

Erratum to: On the Social Validity of Behavior-Analytic Communication: a Call for Research and Description of One Method

The Analysis of Verbal Behavior -     

Hysteresis versus Persistence in Unemployment: A Sceptical Note on Unit Root Tests

ABSTRACT: Previous studies of time-series data suggest that the rate of unemployment is best described as a driftless random walk. This is a far from trivial point because the policy implications of an alternative stationary series can be very different. On the basis of simulated data, this paper demonstrates how the rate of unemployment may appear to be difference stationary, yet is actually trend stationary, and that, contrary to conventional wisdom, the low power of the standard unit root test for stationarity is significant with regard to the conduct of policy. Thus, although the series under investigation may in fact offer little scope for successful policy intervention, the null hypothesis of a unit root may be accepted along with its attendant policy implications. Finally, an alternative test based on a null hypothesis of a stationary process is assessed.     

Predictability of designs which adjust for imbalances in prognostic factors

Minimisation is a method often used in clinical trials to balance the treatment groups with respect to some prognostic factors. In the case of two treatments, the predictability of this method is calculated for different numbers of factors, different numbers of levels of each factor and for different proportions of the population at each level. It is shown that if we know nothing about the previous patients except the last treatment allocation, the next treatment can be correctly guessed more than 60% of the time if no biased coin is used. If the two previous assignments are known to have been the same, the next treatment can be guessed correctly around 80% of the time. Therefore, it is suggested that a biased coin should always be used with minimisation. Different choices of biased coin are investigated in terms of the reduction in predictability and the increase in imbalance that they produce. An alternative design to minimisation which makes use of optimum design theory is also investigated, by means of simulation, and does not appear to have any clear advantages over minimisation with a biased coin.     

Friends First? The Peer Network Origins of Adolescent Dating

The proximity of dating partners in peer friendship networks has important implications for the diffusion of health‐risk behaviors and adolescent social development. We derive two competing hypotheses for the friendship–romance association. The first predicts that daters are proximally positioned in friendship networks prior to dating and that opposite‐gender friends are likely to transition to dating. The second predicts that dating typically crosses group boundaries and opposite‐gender friends are unlikely to later date. We test these hypotheses with longitudinal friendship data for 626 ninth‐grade PROSPER heterosexual dating couples. Results primarily support the second hypothesis: Romantic partners are unlikely to be friends in the previous year or share the same cohesive subgroup, and opposite‐gender friends are unlikely to transition to dating.     

Test–Retest Reliability in Infant Speech Perception Tasks

A long line of research investigates how infants learn the sounds and words in their ambient language over the first year of life, through behavioral tasks involving discrimination and recognition. More recently, individual performance in such tasks has been used to predict later language development. Does this mean that dependent measures in such tasks are reliable and can stably measure speech perception skills over short time spans? Our three laboratories independently tested infants with a given task and retested them within 0–18 days. Together, we can report data from 12 new experiments (total number of paired observations N = 409), ranging from vowel and consonant discrimination to recognition of phrasal units. Results reveal that reliability is extremely variable across experiments. We discuss possible causes and implications of this variability, as well as the main effects revealed by this work. Additionally, we offer suggestions for the field of infant speech perception to improve the reliability of its methodologies through data repositories and crowd sourcing.     

Comparison of Type I error rates and statistical power of different propensity score methods

Propensity score analysis (PSA) is a technique to correct for potential confounding in observational studies. Covariate adjustment, matching, stratification, and inverse weighting are the four most commonly used methods involving propensity scores. The main goal of this research is to determine which PSA method performs the best in terms of protecting against spurious association detection, as measured by Type I error rate, while maintaining sufficient power to detect a true association, if one exists. An examination of these PSA methods along with ordinary least squares regression was conducted under two cases: correct PSA model specification and incorrect PSA model specification. PSA covariate adjustment and PSA matching maintain the nominal Type I error rate, when the PSA model is correctly specified, but only PSA covariate adjustment achieves adequate power levels. Other methods produced conservative Type I Errors in some scenarios, while liberal Type I error rates were observed in other scenarios.     

Fatter or fitter? On rewarding and training in a contest

Competition between heterogeneous participants leads to low-effort provision in contests. A principal can divide her fixed budget between skill-enhancing training and the contest prize. Training can reduce heterogeneity, increasing effort. It also reduces the contest prize, making effort fall. We set up an incomplete-information contest with heterogeneous players and show how this trade-off is related to the size of the budget of an effort-maximizing principal. A selection problem arises implying a cost associated with a win by the inferior player. The principal has a larger incentive to train the laggard, reducing the prize on offer.