Worries, 'weirdos', neighborhoods and knowing people: a qualitative study with children and parents regarding children's independent mobility.

This qualitative study involved focus groups with 132 children and 12 parents in primary and secondary schools in metropolitan and regional areas of Victoria, Australia, to explore experiences and perceptions of children's independent mobility. The study highlights the impact of family routines, neighborhood characteristics, social norms and reference points for decision making. Children reported a wider range of safety concerns than parents, including harm from strangers or traffic, bullying, or getting lost. Children expressed great delight in being independent, often seeking to actively influence parents' decision making. Children's independent mobility is a developmental process, requiring graduated steps and skill building.

Testing for the presence of multiple sources of informative dropout in longitudinal data.

Longitudinal studies tracking the rate of change are subject to patient dropout. This dropout process might not only be informative but also heterogeneous in the sense that different causes might contribute to multiple patterns of informative dropout. We propose a random-effects approach to test for homogeneity of informative dropout that accommodates the realistic situation where reasons for dropout are not fully understood, or perhaps are even entirely unknown. The proposed score test is robust in that it does not depend on the underlying distribution of the informative dropout random effects. The test allows for an additional level of clustering among participating subjects, as might be found in a family study, provided the informative dropout random effects have a known correlation structure.