Health & Place 14 (2008) 693–701 Neighbourhood variations in child accidents and related child and maternal characteristics: Does area definition make a difference? Robin Haynes a,Ã , Andrew P. Jones a , Richard Reading b , Konstantinos Daras a , Alan Emond c a School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK b School of Medicine, Health Policy and Practice, University of East Anglia, Norwich NR4 7TJ, UK c Centre for Child and Adolescent Health, University of Bristol, Bristol BS6 6JS, UK Received 27 July 2007; received in revised form 5 November 2007; accepted 6 November 2007 Abstract Accident occurrence and measures of physical activity, total development and conduct difficulties were recorded for 9391 pre-school children recruited to the Avon Longitudinal Study of Parents and Children (ALSPAC) study in southwest England. Information about their mothers’ age at delivery, post-natal depression, life events, social support and smoking status was also included. Multilevel modelling was used to identify variations between alternative sets of subjective and automated zone design neighbourhoods, which incorporated different boundaries and different scales. The risk of accidents to pre-school children, and most of the characteristics of children and mothers associated with accident risk, varied significantly between neighbourhoods. Differences in the strength of area effects between alternative sets of neighbourhoods were small, although slightly stronger effects were observed in areas with populations less than 4000. Neighbourhoods subjectively defined by planners did not produce stronger effects than computer-generated areas. r 2007 Elsevier Ltd. All rights reserved. Keywords: Accidents; Area effects; Neighbourhood; Modifiable areal unit; ALSPAC Introduction Although ‘‘neighbourhood effects’’ on health have been recognized in many studies (reviewed by Pickett and Pearl, 2001; Diez-Roux, 2001; Macin- tyre et al., 2002), very little is known about the underlying mechanisms and very little experimenta- tion has been done to find out what kind of neighbourhoods have the greatest effect on health. While researchers have been challenged to consider the geographical scales at which processes might operate (Macintyre and Ellaway, 2003) and to com- pare alternative neighbourhood sets (Diez-Roux, 2001; Martikainen et al., 2003), few studies so far have done this. It is well known that so-called ecological associations between variables measured within areas are not stable, but can vary accord- ing to the delineation of the area boundaries and the size of the areas (the ‘‘modifiable areal unit problem’’: Openshaw, 1984). Any geographical area ARTICLE IN PRESS www.elsevier.com/locate/healthplace 1353-8292/$ - see front matter r 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.healthplace.2007.11.001 Ã Corresponding author. Tel.: +44 1603 592554; fax: +44 1603 507719. E-mail address: r.haynes@uea.ac.uk (R. Haynes).