Exact methods of testing the homogeneity of prevalences for correlated binary data

Correlated binary data arise in many ophthalmological and otolaryngological clinical trials. To test the homogeneity of prevalences among different groups is an important issue when conducting these trials. The equal correlation coefficients model proposed by Donner in 1989 is a popular model handling correlated binary data. The asymptotic chi-square test works well when the sample size is large. However, it would fail to maintain the type I error rate when the sample size is relatively small. In this paper, we propose several exact methods to deal with small sample scenarios. Their performances are compared with respect to type I error rate and power. The ‘M approach’ and the ‘E + M approach’ seem to outperform the others. A real work example is given to further explain how these approaches work. Finally, the computational efficiency of the exact methods is discussed as a pressing issue of future work.     

Revisiting the residential electricity demand in the United States: A dynamic partial adjustment modelling approach

In recent years, price policies and price changes derived from environmental regulations have played a more important role to promote residential energy conservation. Using recent annual state-level panel data for 48 states, we estimate a dynamic partial adjustment model for electricity demand elasticities on price and income in the residential sector. Our analysis reveals that in the short run, one unit price increase will lead to 0.142 unit of reduction in electricity use after controlling for the endogeneity of electricity price. Thus, raising energy price in the short run will not give consumers much incentive to adjust their appliances to reduce electricity use. However, in the long run, one unit price increase will lead to almost one unit consumption reduction, ceteris paribus. In addition, we find new evidence that for states of higher per capita GDP, raising the electricity price may be more effective to ensure a cut in consumption.     

Trends in and determinants of technical efficiency of software companies in India

This paper attempts to discuss the trends in and determinants of technical efficiency of software companies in India during 1999–2008 by applying input-oriented DEA model. Based upon the PROWESS Database of CMIE, the efficiencies were estimated for the old and new companies and also for Indian, multinational and group companies. The estimations were made for a sample of 72 software companies, under VRS assumption, as dataset manifested large magnitude of differences owing to the presence of big and small companies in the sample. The sales revenue is taken as output variable, and employment, expenditure on computers and electronics equipments, operating expenditure, power, fuel, and water charges as the input variables. The results and analyses demonstrate that the mean overall technical efficiency of the software industry in India during 1999–2008 was low suggesting that software firms, on an average, were wasting 35% of their inputs. It was found that the number of companies operating on most productive scale size has declined during the period under reference. The results also suggest that Indian-owned companies were more efficient than the foreign-owned and group-owned companies. Contrary to the expectations, exports were not found to have exercised significant impact on the efficiency of Indian software industry.     

Carry a big stick,or no stick at all: Punishment and endowment heterogeneity in the trust game

We investigate the effect of costly punishment in a trust game with endowment heterogeneity. Our findings indicate that the difference between the investor and the allocator’s initial endowments determines the effect of punishment on trust and trustworthiness. Punishment fosters trust only when the investor is wealthier than the allocator. Otherwise, punishment fails to promote trusting behavior. As for trustworthiness, the effect is just the opposite. The higher the difference between the investor and the allocator’s initial endowments, the less willing allocators are to pay back. We discuss the consistency of our findings with social preference models (like inequality aversion, reciprocity), the capacity of punishment (i.e., the deterrence hypothesis) and hidden costs of punishment (i.e., models of intrinsic and extrinsic motivation). Our results are hardly coherent with the first two (inequality aversion and deterrence), but roughly consistent with the latter.     

Being of two minds: Ultimatum offers under cognitive constraints

We experimentally investigate how proposers in the Ultimatum Game behave when their cognitive resources are constrained by time pressure and cognitive load. In a dual-system perspective, when proposers are cognitively constrained and thus their deliberative capacity is reduced, their offers are more likely to be influenced by spontaneous affective reactions. We find that under time pressure proposers make higher offers. This increase appears not to be explained by more reliance on an equality heuristic. Analysing the behaviour of the same individual in both roles leads us to favour the strategic over the other-regarding explanation for the observed increase in offers. In contrast, proposers who are under cognitive load do not behave differently from proposers who are not.     

IS THERE A FISCAL FREE LUNCH IN A LIQUIDITY TRAP?

In this paper, we use a dynamic stochastic general equilibrium model to examine the effects of an expansion in government spending in a liquidity trap. If the liquidity trap is very prolonged, the spending multiplier can be much larger than in normal circumstances, and the budgetary costs minimal. However, given this fiscal free lunch, it is unclear why policymakers would want to limit the size of fiscal expansion. Our paper addresses this question in a model environment in which the duration of the liquidity trap is determined endogenously, and depends on the size of the fiscal stimulus. We show that even if the multiplier is high for small increases in government spending, it may decrease substantially at higher spending levels; thus, it is crucial to distinguish between the marginal and average responses of output and government debt.     

COMMUNICATION,COORDINATION, AND NETWORKS

We study experimentally the role of the network structure of pre‐play communication in determination of outcome and behavior in a multiplayer coordination game with conflicting preferences. We explore the trade‐off between the efficiency and equity of coordination outcomes and its link to the network structure of communication. Our results show substantial variations in both efficiency and equity of coordination outcomes across networks. While, as expected, increasing the length of communication improves the chance of successful coordination, it also reduces the asymmetry in the distribution of coordinated outcomes. We identify behaviors that explain variations in the distribution of coordinated outcomes both within and across networks. In all treatments, coordination is mostly explained by convergence in communication.     

Do stepping-stone jobs exist? Early career paths in the medical profession

In the Netherlands, students who want to become a medical specialist have to enrol in a training program which is in limited supply. During the search for a position as trainee (or “junior medical specialist”), they may accept a temporary job as a medical assistant. We use a micro data set to investigate whether such work experience increases the probability of becoming junior medical specialist. To deal with selectivity, we simultaneously model the transitions from unemployment to trainee, from unemployment to medical assistant, from medical assistant to trainee and from medical assistant to unemployment. We find that a job as medical assistant helps to become a medical specialist. Received: 27 July 2000/Accepted: 31 January 2001 All correspondence to Gerard J. van den Berg. Responsible editor: John F. Ermisch.     

Gender effect on housework allocation: Evidence from Spanish two-earner couples

In this paper we study the reasons behind the asymmetric distribution of housework within Spanish two-earner couples. Spouses' housework times are estimated jointly in a bivariate framework using data from the 1991 Work Situation and Time Use Survey. In order to understand the impact of gender-specific factors on the observed allocation of housework, we perform estimations that are in line with the Oaxaca decomposition. Our results suggest that the unequal division of domestic work between wives and husbands in our sample is mainly explained by gender-specific effects rather than by differences in their observable characteristics. All correspondence to Daniel Miles. We thank Juan F. Jimeno, a co-editor and two anonymous referees for helpful comments and the Spanish Instituto de la Mujer for providing us with the data. Financial support from the Cátedra de Estudios Feministas-Caixanova and from the Spanish Dirección General de Ense?anza Superior, grant number BEC2001-1270, is also gratefully acknowledged. Responsible editor: Daniel S. Hamermesh.     

Self-selection,earnings, and out-migration: A longitudinal study of immigrants to Germany

In this paper we examine the process of out-migration and investigate whether cross-sectional earnings assimilation results suffer from selection bias due to out-migration. Our 14 year longitudinal study reveals that emigrants are negatively selected with respect to occupational prestige and to stable full time employment. Our results show no selectivity with respect to human capital or gender. The likelihood of return migration is strongly determined by the range and nature of social attachments to Germany and origin countries. It is also the highest during the first five years since arrival, and grows higher toward retirement. Selective emigration, however, does not appear to distort cross-sectional estimates of earnings assimilation in a relevant way.All Correspondence to Douglas S. Massey. This study has been made possible through various research visits to DIW Berlin and IZA in Bonn. We are grateful for the access to the data, and many useful comments on various drafts by Klaus F. Zimmermann. Earlier drafts were presented at the annual conference of the Population Association of America in Atlanta, and research seminars at Princeton University and IZA, Bonn. We wish to thank many participants for stimulating discussions and useful comments. We have benefitted in making revisions from the comments of three anonymous referees. Responsible editor: Klaus F. Zimmermann.