I examine the sample selection bias in portfolio horse race. Numerous studies propose mean-variance portfolio rules to …

trends at different points in their life cycle then matched sample methods may introduce bias if the life cycle movement in … pricing effects and then examines the bias it can introduce in measured inflation. A large US supermarket scanner data set for … change is important across a range of products and cities. To explore the bias introduced by these movements we use …

mechanism may differ among the levels of nonresponse, and merging the levels of nonresponse may cause bias in the results of the …

first characterize the biases in both network statistics and estimates of network effects under non-random sampling … theoretically and numerically. Sampled network data systematically bias the properties of observed networks and suffer from non …-classical measurement-error problems when applied as regressors. Apart from the sampling rate and the elicitation procedure, these biases …

causal model. This ‘no randomisation bias’ assumption is generally untestable but if violated would undermine the causal …