Looking beneath and in-between the hidden surfaces: a critical review of defining, measuring and contextualizing mental health service disparities in the child welfare system

•There is lack of consistency in defining and measuring disparities.•Public health scholars offer insight on how to measure disparities.•Despite progress, prior definitions of disparities conceal more than they reveal.•More research is warranted to generate a clear definition of disparities.•Methodological advancements are needed to address determinants of disparities.

Efforts to understand and respond to racial and ethnic disparities in referrals to and use of mental health services among children involved in the child welfare system are constrained by the lack of consistency in defining and measuring disparities and the lack of clarity as to what causal mechanisms sustain patterns of disparate treatment. Recent developments in the field of public health offer some insight as to how our understanding of similar disparities in child welfare may be advanced. Despite advancements, there is still an insufficient knowledge base from which to offer an alternative definition of disparities that illuminates conceptual and methodological innovation in child welfare research. Based on a critical review of the literature, more exploratory and etiological research grounded in implementation of advanced metrics and multivariate methods is warranted to generate a clear definition. Recommendations are offered to address conceptual ambiguity.