In the well-known `critical mass' model of social interactions, aggregate behaviour exhibits multiple equilibria if the influence of group behaviour on individual behaviour exceeds some fairly high threshold. I demonstrate that this property depends on an implicit assumption that the relevant...

A number of studies have indicated that peer smoking is a highly influential factor in a young person's decision to smoke. However, this finding is suspect, because the studies often fail to account for selection and simultaneity bias. This paper develops an econometric model of youth smoking...

We examine the contribution of differences in school environments to the gap in education outcomes between Aboriginal and non-Aboriginal students. We find both substantial school-level segregation of Aboriginal and non-Aboriginal students and a substantial gap in test scores. Conventional...