… Do as the Romans do. A model of conformity with the endogenous formation of preferences

This note is an answer to a previous model on conformity in public goods contributions developed by Carpenter (2004), where a population evolution is allowed according to the standard replicator dynamic (Taylor and Jonker, 1978, Maynard Smith, 1982). To confirm his theoretical prediction, Carpenter developed an experiment showing that free riding actually grows faster when agents have the information necessary to conform. The model and the experiment are, however, inherently different, for the time scales of the model are not able to capture the short run convergence of behavior in the experimental laboratory.We here present a model of conformity which offers the same laboratory results as Carpenter without resorting to evolutionary models, and also gives agents the chance to adopt different strategies implying various levels of cooperation.     

Supply chain agility as an acclimatisation process to environmental uncertainty and organisational vulnerabilities: insights from British SMEs

Abstract

Even though supply chain agility (SCA) has been considered an essential concept in supply chain management (SCM) research, the way it is experienced and manifested, especially by small and medium-sized enterprises (SMEs), has received much less attention. Our purpose is to focus on SME organisational vulnerabilities in the context of increased environmental uncertainty, and explore how SCA is developed and applied by SMEs amid their vulnerabilities. By relying on insights from comparative case studies of three British SMEs, we examine SME SCA as an acclimatisation process and delve into SMEs’ experiences of facing environmental uncertainty while developing and applying SCA. Our findings highlight that organisational attitudes underlie how SMEs perceive environmental uncertainty, tackle organisational vulnerabilities and develop SCA as an acclimatisation process. Our findings also reveal that resource constraints, supply chain relationships, interorganisational power dynamics, and access to information play important roles in developing SCA.     

Four Motives for Community Involvement

A conceptual analysis is offered that differentiates four types of motivation for community involvement: egoism, altruism, collectivism, and principlism. Differentiation is based on identification of a unique ultimate goal for each motive. For egoism, the ultimate goal is to increase one's own welfare; for altruism, it is to increase the welfare of another individual or individuals; for collectivism, to increase the welfare of a group; and for principlism, to uphold one or more moral principles. As sources of community involvement, each of these four forms of motivation has its strengths; each also has its weaknesses. More effective efforts to stimulate community involvement may come from strategies that orchestrate motives so that the strengths of one motive can overcome weaknesses of another. Among the various possibilities, strategies that combine appeals to either altruism or collectivism with appeals to principle may be especially promising.     

Testing variance components in balanced linear growth curve models

It is well known that the testing of zero variance components is a non-standard problem since the null hypothesis is on the boundary of the parameter space. The usual asymptotic chi-square distribution of the likelihood ratio and score statistics under the null does not necessarily hold because of this null hypothesis. To circumvent this difficulty in balanced linear growth curve models, we introduce an appropriate test statistic and suggest a permutation procedure to approximate its finite-sample distribution. The proposed test alleviates the necessity of any distributional assumptions for the random effects and errors and can easily be applied for testing multiple variance components. Our simulation studies show that the proposed test has Type I error rate close to the nominal level. The power of the proposed test is also compared with the likelihood ratio test in the simulations. An application on data from an orthodontic study is presented and discussed.     

Bayesian and Robust Bayesian analysis under a general class of balanced loss functions

For estimating an unknown parameter θ, we introduce and motivate the use of balanced loss functions of the form L_{r, w, d0}(q, d)=wr(d₀, d)+ (1-w) r(q, d){L_{rho, omega, delta_0}(theta, delta)=omega rho(delta_0, delta)+ (1-omega) rho(theta, delta)}, as well as the weighted version q(q) L_{r, w, d0}(q, d){q(theta) L_{rho, omega, delta_0}(theta, delta)}, where ρ(θ, δ) is an arbitrary loss function, δ ₀ is a chosen a priori “target” estimator of q, w ? [0,1){theta, omega in[0,1)}, and q(·) is a positive weight function. we develop Bayesian estimators under L_{r, w, d0}{L_{rho, omega, delta_0}} with ω > 0 by relating such estimators to Bayesian solutions under L_{r, w, d0}{L_{rho, omega, delta_0}} with ω = 0. Illustrations are given for various choices of ρ, such as absolute value, entropy, linex, and squared error type losses. Finally, under various robust Bayesian analysis criteria including posterior regret gamma-minimaxity, conditional gamma-minimaxity, and most stable, we establish explicit connections between optimal actions derived under balanced and unbalanced losses.     

Economic burden of tuberculosis and its coping mechanism at the household level in Pakistan

Despite the availability of free medicines under the Directly Observed Treatment Short-course (DOTS) strategy, the treatment of tuberculosis (TB) still involves high costs that push people into poverty. This study aims to assess the resulting economic burden of TB and examine the coping mechanisms practiced at the household level in Pakistan. A cross-sectional study was conducted at TB centers by interviewing 269 patients. Statistical tests and binary logistic regression were used to explore the relationship between catastrophic health expenditures (CHE) and socio-economic factors. Results show that the incidence and intensity of CHE were higher for households in the lower income-quintile. Several coping strategies were practiced and varied among the different income-quintiles. The independent determinants of CHE were as follows: age >40 years, male-patient, location, earner-ratio, patient as the earner, caretaker visits, treatment delay, and co-morbidity. It is recommended that health policymakers develop post-MDGs TB-control strategies to ensure free TB-services with financial protection around the globe.     

Information matrix for a mixture of two inverse gaussian distributions

In this paper, Fisher information matrix about the five parameters ρ, μ_:1, μ², λ¹and λ²of a mixture of two Inverse Gaussian density functions is obtained. The Leguerre-Gauss quadrature formula is used to evaluate the essential integral on which the twenty five elements of the information matrix are based. Results involving the computation of the information about p are compared with those involving both the power series expansion and Simpson's method of integration. Laguerre-Gauss quadra-ture was found to lead to good approximations as compared with other methods. It was therefore chosen for the computations of the elements of the information matrix.     

A note on the mean residual life of a coherent system with a cold standby component

In this paper, we investigate the effect of a cold standby component on the mean residual life (MRL) of a system. When the system fails, a cold standby component is immediately put in operation. We particularly focus on the coherent systems in which, after putting the standby component into operation, the failure of the system is due to the next component failure. For these systems, we define MRL functions and obtain their explicit expressions. Also some stochastic ordering results are provided. Such systems include k-out-of-n systems. Hence, our results extend some results in literature.     

Expenditure Differences of University Degree Holders Across Occupational Sectors in Malaysia

This study was motivated by the key role university degree holders play in Malaysia's vision for the future and by concerns expressed about the drift of university degree holders from one sector to another. A questionnaire was mailed to a sample of 400 Malaysian families that had at least one member who held a university degree. The objective was to elicit details of the household economic situation of respondents, with special reference to the differences in expenditure patterns between families whose degree holder worked in higher education, government, or the private sector.Results of tobit analysis of expenditures show that there are some differences between the sectors regarding expenditure patterns, but the differences are not as great as expected. Nevertheless, university-educated persons in the private sector seem to have somewhat different expenditure patterns than their counterparts in other sectors.