Measuring and analysing social efficiency in the production of maternal health services in Mexico, 2008-15.

'Social efficiency' (SE) denotes the capacity of health systems to ensure equitable access to quality health services at no financial risk to users. Mexico and other low- and middle-income countries have rarely studied the performance of their health systems from an SE perspective. We propose a metric for assessing SE in the production of maternal health services in the public sector among populations without social security, analysing contextual correlates of the demand for these services. Analysis was based on administrative data collected from the 243 health jurisdictions (HJs) in Mexico for the period 2008-15. We defined production inputs as the availability of physical and human resources and social product as the unweighted sum of social sub-products, including an equitable distribution of maternal health resources, the provision of quality maternal health care and financial protection for users. We described the SE scores, the main contextual characteristics as well as those related to the demand for maternal health services. We then performed a variance decomposition analysis of the SE score by component and estimated the SE territorial concentration patterns. Finally, we identified the structural characteristics modelling SE by means of a spatial autoregressive panel data model with fixed effects by year. The SE score rose from 57.7% in 2008 to 71.9% in 2015 (P < 0.01), with its quality component accounting for the largest proportion of variance (30%). SE peaked in HJs with low social marginalization and rurality, and with service demand characterized by low parity and older populations. Different SE levels demonstrated territorial concentration patterns. Analysing SE as a metric for health system performance offers elements that contribute to the achievement of UHC as well as to the design and implementation of effective maternal health interventions intended particularly for the most socially vulnerable sectors of the population.