Probit Models with Binary Endogenous Regressors

Sample selection and endogeneity are frequent causes of biases in non-experimental empirical studies. In binary models a standard solution involves complex multivariate models. A simple approximation has been shown to work well in bivariate models. This paper extends the approximation to a trivariate model. Simulations show that the approximation outperforms full maximum likelihood while a least squares approximation may be severely biased. The methods are used to estimate the influence of trust in the parliament and politicians on voting- propensity. No previous studies have allowed for endogeneity of trust on voting and it is shown to severely affect the results.endogeneity; multivariate probit; approximation; Monte Carlo simulation

Competitive ability of grain legume-barley intercrops towards volunteer crops and weeds

Field pea (Pisum sativum L.) and blue lupin (Lupinus angustifolius L.) were either sole cropped or inter-cropped with barley (Hordeum vulgare L.) at two levels of nitrogen application to determine the effects of interspecific interaction in an intercrop and nitro-gen fertility on competitive ability towards volunteer crops - exemplified by red clover (Trifolium pratense). The dynamically change of competitive ability by intercropped species over time was shown to be im-portant in order to reduce opportunities for growth of volunteer crops and weed

Measured lives in educational psychology

Why is the work of educational researcher John Hattie’s work so popular today? This is the question we will try to answer in this paper. Based on a very large empirical database, Hattie calculates the effects of numerous educational interventions and factors influencing student achievements. Despite documented methodological flaws in his work, Hattie’s work keep attracting the attention of policy makers, teachers and educational researchers all over the world. We propose to understand thepopularity of Hattie’s work in relation to the ongoing debate about the legitimation of schooling – using Habermas’ (1976) work Legitimation Crisis as point of departure. Our claim is that Hattie is offering a theoretical synthesis of effective teaching as a way to legitimize modern schooling. However, there are a number of problems with this synthesis, most notably that it does not include the pupils’ intentions for participating