social behaviour in work absence by making use of a large scale randomized experiment we test whether social behaviour is important for work absence due to illness the individuals treated in the experiment were exposed to less monitoring of their eligibility to collect sickness insurance benefits which sharply increased their non monitored work absence this exogenous variation is exploited in two complementary analyses in both analyses we find significant social behaviour effects using detailed data we conclude that the social behaviour effects most likely stem from fairness concerns

modelling the joint determination of household labour supplies and commodity demands in addition to choosing the allocation of total expenditure between commodities households may also be able to make decisions over the allocation of their time between market work and leisure in both theoretical and empirical work it has often been the case that these decisions have been analysed separately in this paper we stress the theoretical attractions of considering the joint determination of the allocation of time between work and leisure and the allocation of total expenditure between commodities in a utility maximising framework using a sample of individual households we attempt to evaluate the empirical importance of the joint determination model over the separate determination of labour supplies and commodity demands our approach follows that of abbott and ashenfelter i976 phlips i978 barnett i979 deaton and muellbauer i980 and atkinson and stern i980 here we pay particular attention to the following four important aspects of household decision making over commodity demand and labour supply the first concerns the commonly assumed restriction on the household s preferences of weak separability between goods and leisure this assumption allows the estimation of commodity demand systems and engel curves that exclude wage rate variables in cross section household budget data with large variation in wage rates across the sample the invalidity of this assumption would involve a serious mis specification any correlation between the excluded wage variable and the included price income and demographic variables would lead to biased parameter estimates and hence biased estimated elasticities similarly this assumption allows the estimation of labour supply curves that exclude relative price variables and its invalidity could produce biased labour supply elasticities a second aspect of household decision making which we wish to highlight arises from the suspicion commonly alluded to in labour economics texts that primary male workers may not be free to choose their hours of work thus we estimate a matched pair of rationed and unrationed systems following the work of neary and roberts i 980 and deaton and muellbauer i 979 the separability restriction is not unrelated to this point since without it we will see that the rationed hours of work enter demand systems in a complex fashion in effect

a rational expectations model of agricultural supply this work suggests a dynamic linear rational expectations modeling strategy for using time series observations to study the impact of product prices on agricultural production and land allocation the farmer s decision consists of specifying each period the portion of his land to be devoted to the growing of alternative crops the dynamic element in the farmer s problem comes from the technology a quadratic production technology is used the farmer s optimal land allocation decision rules are derived as linear functions of past land allocations expectations of future product prices and other exogenous variables and they can be interpreted as an optimal crop rotation assuming rational expectations and the exogeneity of prices for a small open economy one obtains closed form linear regression equations representing decision rules and stochastic processes these are then estimated and tested using maximum likelihood methods and aggregate data from the egyptian agriculture

agricultural product supplies and input demands regional comparisons governmental agencies at federal state and local levels in the united states are heavily involved in intervention in agricultural input and output markets to effect desired social goals the most pervasive intervention activities occur at the federal level they are available throughout the nation to most producers of specified commodities how

units of measurement and the stone index in demand system estimation the stone index typically used in estimating linear almost ideal demand systems is not invariant to changes in units of measurement which may seriously affect the approximation properties of the model a modification to the stone index or use of a regular price index instead are both desirable practices in estimating linear ai models

playing the fertility game at work an equilibrium model of peer effects we study workplace peer effects in fertility decisions using a game theory model of strategic interactions among coworkers that allows for multiple equilibria using register based data on fertile aged women working in medium sized establishments in denmark we uncover negative average peer effects allowing for heterogeneous effects by worker type we find that positive effects dominate across worker types defined by age or education negative effects dominate within age groups and among low education types policy simulations show that these estimated effects make the distribution of where women work an important consideration beyond simply if they work in predicting population fertility

a model of production with supply management for the canadian agricultural sector the production structure of the canadian agricultural sector is modeled by an output constrained multiproduct profit function to account for the existence of supply management policies the le chatelier effects of supply constraints are illustrated and the comparative statics of supply management is shown to depend under input normality on the type of jointness convexity is tested and accepted and nonjointness is rejected by the estimated normalized quadratic profit function the results support the hypothesis of nonjointness due to allocatable fixed factors decreasing the supply of managed commodities will increase the supply of unrestricted commodities while total input use is reduced

identification and estimation of the linear in means model of social interactions abstract this paper studies identification and estimation of the linear in means model of social interactions using a quasi panel data approach we show how endogenous social effects can be identified in the presence of unobserved group effects

evaluating alternative price expectation models for multiproduct supply analysis abstract neoclassical economic theory provides an important conceptual framework for the analysis of agricultural production theory provides little guidance however in the actual specification of empirical models this paper applies an integrated approach for choosing between price expectation mechanisms in a multiple equation model when the alternatives are non nested nine alternative specifications of market price and policy information are developed price forecasting accuracy non nested tests of hypotheses and out of sample predictive accuracy are examined for agricultural production in iowa the results call into question the reliability of using forecasting accuracy as the sole guide to selecting a price expectation proxy

prices and social behaviour evidence from adult smoking in canadian aboriginal communities this paper provides estimates of tobacco price elasticity explicitly distinguishing between two price effects the direct effect reflecting individual reaction to a price change and the indirect effect whereby price influences the individual by changing community smoking behaviour canada s aboriginal communities are small and secluded allowing for plausible identification of reference groups on a relatively large scale estimates suggest a 10 increase in price decreases daily smoking by 0 91 percentage points 2 11 occasional smoking by 1 24 percentage points 8 27 and average smoking intensity by 0 15 cigarettes per day 2 9 it is found that the indirect effect almost doubles the response to a change in tobacco prices over the direct effect alone

the joint demand for health care leisure and commodities implications for health care finance and access in vietnam abstract this paper explores linkages between the demand for health care providers and the consumption of food non food goods and leisure in vietnam using a mixed continuous discrete dependent variable model cross price elasticities calculated from the model suggest there are strong substitution effects between health care leisure and certain commodities the model allows us to explore the implications of replacing user fees with alternative forms of health care finance such as commodity taxes in particular the results suggest financing public health care services with a non food sales tax rather than user fees would be more progressive and would improve access to care

effect of large scale social interactions on body weight i estimate models of endogenous social interactions in body weight at the county and state levels the results show that dispersion in body weight across time and space in the u s is not clearly excessive and that much of this variation can be attributed to observable individual and regional characteristics models exploiting variants of methods proposed by glaeser et al 2003 fixed effects instrumental variable and split sample instrumental variable methods to address endogeneity suggest that there are not large social multipliers on body weight outcomes the evidence suggests there may be small multipliers on bmi obesity and morbid obesity there is no evidence that underweight is subject to a social multiplier the results are sensitive to specification

understanding regression versus variance tests for social interactions this article considers the relationship between the use of regressions and the use of variance contrast methods to uncover social interactions we illustrate how these methods employ different identifying assumptions and are therefore complementary approaches we also provide formal identification results that extend existing ones for the two methods jel c12 c21 c23 z13 this article is designed to understand the relationshipbetweentwoapproachestotheempirical analysis of social interactions the first approach is the use of linear regressions to uncover social interactions this approach estimates social interaction effects through changes in the conditional linear expectation of individual outcomes when group level variables are included in the conditioning set in econometrics this method was first analyzed by manski 1993 who dubbed it the linearin means model since the group level variables are typically averages of individual variables within the group this model is also studied by brock and durlauf 2001a 2001b cohencole 2006 and graham and hahn 2005 among others durlauf 2004 surveyed empirical studiesof social interactionsbasedonsuch regressions the second approach originally proposed by glaeser sacerdote and scheinkman 1996 and developed into a full inferential procedure by graham 2005 who refers to this approachasvariancecontrasts usesintragroup variation in behavior to infer social interactions the idea in this approach is that social interactions willinduceintragroupdependences in behavior that affect sample variances for intragroup outcomes there has been relatively little work evaluating social interactions using variance contrasts one reason is that with the exception of graham s work there is little formal statistical theory for the approach the purpose of this article was to clarify the relationship between regression and variance contrast tests weclarify how these tests employ different informational assumptions to achieve identification of social interaction specifically we argue that regression and variance contrast approaches correspond to identification via exclusion restrictions in the one case and covariance restrictions on errors in the other as such the two approaches replicate the classes of identification strategies that appear in the classical simultaneous equations literature see fisher 1966 for a classic treatment the remainder of the article is organized as

non price rationing and the choice of medical care providers in rural cote d ivoire this paper investigates the role of travel time in rationing medical care services in a developing country where monetary prices are zero a nested multinomial logit model of provider choice is estimated using 1985 data from rural cote d ivoire unlike previous studies of health care demand in developing countries our results indicate that travel time plays an important role in rationing health care and that medical care demand for poorer individuals is substantially more travel time elastic than for richer individuals

an indirect test for the specification of expectation regimes this paper develops an empirical strategy for testi ng competing hypotheses of expectation regimes when direct measures of expectati ons are unavailable the procedure takes as given an assumed structural relation ship between expected values of exogeneous variables and a given decision variab le by imposing different expectation regimes on this model the authors obtain an artificial nesting of the hypothesized regimes which allows us to test whethe r any specification dominates this methodology is extended to multipleequation applications with any number of hypothesized expectation regimes the tests are illustrated using a model of the response of county level farm acreage allocati on to expected commodity prices copyright 1986 by mit press

flexible discrete choice demand models consistent with utility maximization an application to health care demand policies a considerable literature has developed to estimate the economic determinants of health care provider choice one important goal of this literature has been the estimation of price elasticities of health care demand particularly in rural areas of developing countries where debates continue regarding appropriate levels of user fees in government health facilities world bank accurate estimation of price elasticities is crucial to evaluating the trade offs between health promotion and revenue generation in rural areas where poorly funded government clinics are often consumers only accessible health care choices however the exact empirical implementation of demand estimation with discrete data has be

participation and investment decisions in a retirement plan the influence of colleagues choices abstract this paper investigates whether peer effects play an important role in retirement savings decisions we use individual data from employees of a large university to study whether individual decisions to enroll in a tax deferred account plan sponsored by the university and the choice of the mutual fund vendor for people who choose to enroll are affected by the decisions of other employees in the same department to overcome the identification problems we divide the departments into sub groups along gender status age and tenure lines and we instrument the average participation of each peer group by the salary or tenure structure in this group our results suggest that peer effects may be an important determinant of savings decisions

numeraire choice in agricultural supply analysis should the choice of numeraire price for modelling profit functions be arbitrary or is more careful study needed here the choice of numeraire is examined using tests for models specification and out of sample predictive accuracy based on the crop and livestock data obtained from iowa the results of this study indicate that for this data set and functional form it does indeed make a difference which numeraire you choose this is in contrast to previous studies which in general indicated that the choice of numeraire equation is arbitrary or more commonly offered no justification for the netput chosen

numeraire choice in normalized quadratic functional forms a semi nested test procedure is developed for choosing the numeraire for a normalized quadratic profit function when too few observations exist for nested hypothesis testing and when too many alternatives exis for conventional non nested testing sensitivity of empirical results to choice of numeraire price is examined using agricultural data for the us and ten multistate regions few test conclusions vary by numeraire but own price input demand elasticities differ greatly

multiproduct supply and input demand in u s agriculture two sets of u s agricultural output supply and input demand relationships including cross price effects are reported for five commodity groups and four variable input groups for the 1951 82 period they are obtained by direct econometric estimation on u s data and by geographic aggregation from published econometric estimates for each of ten regions comprising the contiguous forty eight states the supply and demand formulations are specified on the assumptions of competitive behavior and an underlying normalized quadratic profit function the effects of upward sloping input supply curves are examined at the national level

identification of endogenous social effects the reflection problem this paper examines the reflection problem that arises when a researcher observing the distribution of behaviour in a population tries to infer whether the average behaviour in some group influences the behaviour of the individuals that comprise the group it is found that inference is not possible unless the researcher has prior information specifying the compisition of reference groups if this information is available the prospects for inference depend critically on the population relationship between the variables defining reference groups and those directly affecting outcomes inference is difficult to implossible if these variables are functionally dependent or are statistically independent the prospects are better if the variables defining reference groups and those directly affecting outcomes are moderately related in the population

nonparametric tests of utility maximization and weak separability for consumption leisure and money some of the most fundamental assumptions of economics are utility maximization and weak separability of the arguments in the represen tative consumer s utility function this paper contains results from nonparametric tests of these assumptions about consumer behavior the authors find that quarterly per capita data on consumption goods le isure and monetary assets are consistent with utility maximization further consumption goods and leisure meet necessary and sufficient conditions for weak separability additionally one grouping of relat ively liquid monetary assets meets the necessary conditions for weak separability they also test and find no evidence of homothetic prefe rences copyright 1987 by mit press

fertility choice mortality expectations and interdependent preferences an empirical analysis we investigate the empirical relationship between child mortality and fertility across 46 low and middle income countries specifically we model the effect of mortality expectations and interdependent fertility preferences on fertility the direct marginal effect of mortality expectations on fertility is larger than zero but less than unity this implies that a decrease in mortality rates leads to a decrease in children born but to an increase in the number of surviving children and hence the rate of population growth taking into account interdependent fertility preferences whereby an individual s fertility choice affects the fertility decisions of others the marginal effect of mortality expectations on fertility becomes one hence if we allow for both mortality expectations and the amplifying effect of interdependent fertility preferences a decrease in child mortality has no net effect on the rate of population growth

social interactions and schooling decisions abstract the aim of this paper is to study whether a child s schooling choices are affected by the schooling choices of other children identification is based on a randomized targeted intervention that grants a cash subsidy conditional on school attendance to a subgroup of eligible children within small rural villages in mexico progresa this policy change spills over to ineligible children if social interactions are relevant results indicate that the eligible children tend to attend school more frequently and the ineligible children acquire more schooling when the subsidy is introduced in their local village moreover the overall effect of progresa on eligible children is the sum of a direct effect due to cash transfers and an indirect effect due to changes in peer group schooling interestingly the social interactions effect is almost as important as the direct effect