Self-selection can bias estimates of treatment effects from randomized experiments if one is interested not merely in the effect of treatment on the treated, but in extrapolating results to the general population. This paper employs the Roy model to study this problem in the context of medical trials. The main insight is that, as the probability of receiving active treatment rises, patients who...

This study adopts a GNP function approach in order to examine the impact of migrant labour on domestic factors of production in the United Kingdom. We also examine the relationship between imports and migrants, which are two different facets of globalisation. We find that an increase in the number of unskilled migrants reduces the wages of unskilled domestic workers. However the quantitative im...

Central and Eastern Europe countries are in the political and economic transitional process of merging with the European Union. How has foreign investment already transformed these countries’ economic sectors and how will it affect the national economies in terms of capitalization across economic sectors in the near future? Our prime consideration is portfolio investment impact on the dynamics ...

Using many valid instrumental variables has the potential to improve efficiency but makes the usual inference procedures inaccurate. We give corrected standard errors, an extension of Bekker (1994) to nonnormal disturbances, that adjust for many instruments. We find that this adujstment is useful in empirical work, simulations, and in the asymptotic theory. Use of the corrected standard errors ...

This paper addresses the choice of an optimal smoothing parameter for local polynomial matching. A version of Empirical Bias Bandwidth Selection (EBBS) proposed by Ruppert (1997) is applied to account for the MSE computation of the matching estimator. Thereby, an estimator for the large sample variance of the local polynomial matching estimator is also provided. A Monte Carlo study indicates be...

I use data from the South African Social Giving Survey to investigate the role of social capital and motivations for giving to formal charities and beggars. Results suggest that both impure altruism and inequality aversion positively influence giving to formal charities but they have no influence on giving to beggars. The role of social capital is varied. Members of informal insurance groups ar...

Existing studies of fiscal policy interactions are based on single equation models of either taxation or expenditures, without specifying the underlying social welfare function, without taking account of budget constraints and without allowing for cost differences between jurisdictions. Taking all this into account, we derive an extended version of the linear expenditure system (LES) with polic...

In this paper, I give a personal view on the development of the field of spatial econometrics during the past 30 years. I argue that it has moved from the margins to the mainstream of applied econometrics and social science methodology. I distinguish three broad phases in the development, which I refer to as preconditions, take off and maturity. For each of these phases I describe the main meth...

In many applications, covariates are not observed but have to be estimated from data. We outline some regression-type models where such a situation occurs and discuss estimation of the regression function in this context. We review theoretical results on how asymptotic properties of nonparametric estimators differ in the presence of generated covariates from the standard case where all covariat...

The Identification and Economic Content of Ordered Choice Models with Stochastic Thresholds This paper extends the widely used ordered choice model by introducing stochastic thresholds and interval-specific outcomes. The model can be interpreted as a generalization of the GAFT (MPH) framework for discrete duration data that jointly models durations and outcomes associated with different stoppin...