New Partner, New Order? Multipartnered Fertility and Birth Order Effects on Educational Achievement.

A substantial amount of research shows that younger siblings perform worse than their older sisters and brothers in several socioeconomic outcomes, including educational achievement. Most of these studies examined stable families and excluded half-siblings. However, the increasing prevalence of multipartnered fertility implies that many children grow up in nonnuclear families.

Segregation within school classes: Detecting social clustering in choice data.

We suggest a new method for detecting patterns of social clustering based on choice data. The method compares similar subjects within and between cohorts and thereby allows us to isolate the effect of peer influence from that of exogenous factors. Using this method on Norwegian register data, we address the question of whether students tend to cluster socially based on similar background.

Immigrant mothers' preferences for children's sexes: A register-based study of fertility behaviour in Norway.

Parental sex preferences have been documented in many native populations, but much less evidence is available on immigrants' preferences for the sexes of their children. Using high-quality longitudinal register data from Norway, a country with a recent immigration history, we estimate hazards regression models of third birth risks by the sex composition of the first two children. A central question in the extant literature is whether the sex preferences of immigrant mothers match those observed in their country of origin, or if cultural adaption to local conditions is more important.

Illicit use of opioid substitution drugs: prevalence, user characteristics, and the association with non-fatal overdoses.

Background And Aims: Diversion of opioid substitution drugs (OSD) is of public concern. This study examined the prevalence, frequency, and predictors of illicit OSD use in a group of injecting drug users (IDUs) and assessed if such use was associated with non-fatal overdoses.

Methods: Semi-annual cross-sectional interviews conducted in Oslo, Norway (2006-2013), from 1355 street-recruited IDUs.