Assessing the reliability and validity of the Northern Ireland Multiple Deprivation Measure 2017

Given that the Northern Ireland Multiple Deprivation Measure (NIMDM 2017) is widely used by administrative data researchers, we wanted to investigate whether the measure and its seven domains accurately reflect what they were designed to, and whether the measure is associated with health outcomes in the ways one would expect. Accessing NIMDM 2017 domain-indicator data via the NI Neighbourhood Information Service, and linking NIMDM data to hospital admissions data, we conducted our analyses in two-phases.

Phase 1 revealed that indicators within some domains were weakly associated and, therefore, did not seem to be measuring the same construct. Some indicators were also more highly associated with indicators in other domains rather than with those in their own domain. Finally the inferred seven-domain structure of the measure was not supported by the data.
Phase 2 revealed that associations between deprivation level and health outcomes were extremely weak. While higher deprivation scores were associated with an increased risk of hospital admission for chronic obstructive pulmonary disease (COPD), substance related mental health disorder, and depression, associations with the other physical and mental health conditions were negligible.

Overall, our findings suggest that the current NIMDM may not be performing optimally, and that the statistical methods used to create the measure, may not be entirely consistent with how deprivation is most commonly conceptualised. We hope that these findings may be useful for the development of future iterations of the measure.