Validation of a deprivation index for public health: a complex exercise illustrated by the Quebec index.

INTRODUCTION: Despite the widespread use of deprivation indices in public health, they are rarely explicitly or extensively validated, owing to the complex nature of the exercise.

METHODS: Based on the proposals of British researchers, we sought to validate Quebec's material and social deprivation index using criteria of validity (content, criterion and construct validity), reliability and responsiveness, as well as other properties relevant to public health (comprehensibility, objectivity and practicality).

RESULTS: We reviewed the international literature on deprivation indices, as well as publications and uses of the Quebec index, to which we added factual data.

CONCLUSION: Based on the review, it appears that the Quebec index responds favourably to the proposed validation criteria and properties. However, additional validations are required to better identify the contextual factors associated with the index.