An extended generalised partially linear single-index (EGPLSI) model provides flexibility of a partially linear model and a single-index model. Furthermore, it also allows for the analysis of the shape-invariant specification. Especially, since it does not only provide the flexibility of a...

This paper attempts to provide empirical evidence of the positive definiteness of the mean income effect matrix, a sufficient condition for market demand to satisfy the law of demand derived by Härdle, Hildenbrand and Jerison [HHJ(1991)]. Increasing heterogeneity in spending of populations of...

This paper presents evidence that the quality of survey data on household incomes systematically improves across waves of a panel. Our estimates indicate that the effect of being interviewed for a second time is to increase the mean of reported monthly income by £142 (8 percent). Dependent...