This study presents several extensions of the most familiar models for count data, the Poisson and negative binomial models. We develop an encompassing model for two well-known variants of the negative binomial model (the NB1 and NB2 forms). We then analyze some alternative approaches to the standard log gamma model for introducing heterogeneity into the loglinear conditional means for these mo...

We use a random-effects model to find the factors that affect the student evaluation of teaching (SET) scores. Dataset covers 6 semesters, 496 undergraduate courses related to 101 instructors and 89 disciplines. Our empirical findings are: (i) the class size affects negatively the SET score; (ii) instructors with more experience are better evaluated, but these gains reduce over time; (iii) part...

Unobserved heterogeneity among childbearing women makes it difficult to isolate the causal effects of smoking and prenatal care on birth outcomes (such as birthweight). Whether or not a mother smokes, for instance, is likely to be correlated with unobserved characteristics of the mother. This paper controls for such unobserved heterogeneity by using state-level panel data on maternally linked b...

This paper examines the effect of trade openness on the productivity of skilled and unskilled labor in a group of 36 developing countries using panel data and fixed effect approach. We have developed and utilized an empirical model that readily lends itself to testing the hypothesis posed. Our results support the hypothesis that trade openness has a positive and significant impact on labor prod...

IND Pub Traditional estimates that often find minimum wage disemployment effects include controls for state unemployment rates and stateand year-fixed effects. Using CPS data on teens for the period 1990–2009, we show that such estimates fail to account for heterogeneous employment patterns that are correlated with selectivity among states with minimum wages. As a result, the estimates are ofte...

In cross-national data on individual and country-level characteristics, the variance of log annual income is shown to correlate positively with indicators of redistribution. The database comes from the Panel Comparability (PACO) project, affiliated with the Luxembourg Income Study (LIS), a first effort to provide comparable panel data across a broad range of countries. Countries in the sample i...

This paper reports the findings from a discrete choice experiment study designed to estimate the economic benefits associated with rural landscape improvements in Ireland. Using a mixed logit model, the panel nature of the dataset is exploited to retrieve willingness to pay values for every individual in the sample. This departs from customary approaches in which the willingness to pay estimate...

We estimated the short-term effect of depression on labor market outcomes using data from the 2004-2009 Medical Expenditure Panel Survey. After accounting for the endogeneity of depression through a correlated random effects panel data specification, we found that depression reduces the likelihood of employment. We did not, however, find evidence of a causal relationship between depression and ...

Do Home Computers Improve Educational Outcomes? Evidence from Matched Current Population Surveys and the National Longitudinal Survey of Youth 1997 Nearly twenty million children in the United States do not have computers in their homes. The role of home computers in the educational process, however, has drawn very little attention in the previous literature. We use panel data from the two main...