BACKGROUND/ RATIONALE: Findings on the long-term effects of the number of hours that a child spends in daycare (as well as the time that the child begins attending daycare) on maladjustment are mixed. For example, in 2010, Vandel et al found no significant association between the amount of time spent in center-care and a long-term effect of that daycare on a child's cognition. A limitation of this study, however, is that it has not explored the age of onset that a child begins daycare, but rather, the amount of daycare per day or week. Additionally, there was no recorded entry-level assessment, when beginning formal education (Vandell, Burchinal, Vandergrift, Belsky & Steinberg, 2010). However, studies have revealed that children attending daycares also exhibit greater amounts of childhood problematic behavior, thus suggesting that there may factors that influence the impact of daycare on a child's behavior (Vandell, Burchinal, Vandergrift, Belsky & Steinberg, 2010; Belsky, 2001; Lamb & Ahnert, 2006; Loeb et al., 2007). While the study of Vandel et al is impressive, it has been conducted on a sample within the United States of America, not among a British cohort (thus the appeal of analyzing data gathered from the ALSPAC sample). Accordingly, no cross-cultural comparisons have been made, nor have any similar studies been conducted with a cohort from a different origin than the United States. This study plans to use trajectory analysis with hours of usage of non-familial daycare as the repeatedly measured outcome at ages 2, 3, 4 and 5, as well as the age at which the child first attended daycare. Secondary analysis will assess the contributions of family risk (e.g. poverty, maternal warmth, parenting styles) and quality of daycare (e.g. the staff-child ratio).

PRINCIPAL AIMS: The aim of this study is to use trajectory analysis to determine how the onset of when a child begins daycare and how the number of hours spent in daycare later contributes to the level of socio-emotional maladjustment and poor academic standing at formal school entry. We will explore this query by means of group-based trajectory analysis anticipating finding a trajectory of children who start daycare early, and spend a relatively high amount of hours per week in daycares (i.e. those on the high trajectory path) will exhibit an increased maladjustment. We will be using the computer software programs Mplus v.6.1 and STATA v.10 to conduct our trajectory analysis.