Those cases were merged with a restructured NCANDS file reflecting the same six years of data, resulting in a file that included 1,942 cases in which a child's first spell in care corresponded with the NCANDS submission window.
The resulting Chapin Hall and NCANDS file was merged with SDM data for the same group of children in the same window, resulting in 1,423 cases with data from all three sources.
Given the tendency for some states to consider sibling groups in placement decisions (Herrick & Piccus, 2009) and studies suggesting that large numbers of children have a sibling in out-of-home care at the same time (Festinger, 1994; Shaw, 2006), likely sibling groups were identified using the NCANDS report identification number as a proxy for family units.
The present analyses define maltreatment to include both abuse and neglect and rely on the same standard definitions of maltreatment, abuse, and neglect as used in the NIS-4, NCANDS, and California data bases.
A final question concerns the appropriateness of combining data from NCANDS and NIS-4, as is done in the analyses of national sample data reported below.
Third, the present paper implicitly assumes that the conceptual and operational definitions of child maltreatment used by NCANDS, NIS and similar sources are appropriate for all racial and ethnic groups and that their incidence estimates are accurate and stable.