Measuring Coverage in MNCH: Determining and Interpreting Inequalities in Coverage of Maternal, Newborn, and Child Health Interventions

Abstract

In a PLOS Medicine Review, Aluísio Barros and Cesar Victora provide a practical guide to measuring and interpreting inequalities in the coverage of maternal, newborn, and child interventions in low- and middle-income countries using data collected by large household surveys.

Mensuração de desigualdades sociais em saúde: conceitos e abordagens metodológicas no contexto brasileiro*

“…Although the SII was conceived based in a linear regression, in general the logistic regression is more adequate for its calculation because usually it is applied to coverage of indicators and prevalence of health outcomes, avoiding linear predictions out of the boundaries of an expected interval of a proportion (from 0 to 100). 16 With regard to the proportions, both the absolute differences between group and the SII vary from -100 to 100 p.p., and values close to zero are expected when there is no inequality. Positive values reveal that the health indicator, be it the coverage of an intervention or the prevalence of a health risk, is more frequent in the most privileged group -for example, in the wealthiest group or the group with higher education.…”

“…It represents absolute difference, in predicted values, of a health indicator between the most privileged individuals and the less privileged individuals in terms of socioeconomic indicators, taking into consideration the entire distribution of the stratification variable using the adequate regression model. 4,16,17 Therefore, the SII is calculated as the difference, in percentage points, between the estimated values for the extreme groups of a given stratification variable. Although the SII was conceived based in a linear regression, in general the logistic regression is more adequate for its calculation because usually it is applied to coverage of indicators and prevalence of health outcomes, avoiding linear predictions out of the boundaries of an expected interval of a proportion (from 0 to 100).…”

“…The main methodological approach consists of evaluating the time trends of summary indexes of inequalities (such as the SII and the CIX), which reinforces once again how complementary the absolute and relative measures are to each other. 16,25 In a hypothetical scenario in which the coverage of a given intervention is, at the beginning of the evaluation, 40% among the richest and of 20% among the poorest, a relative measure based on the In Figure 3(B), the CIX corresponds to twice times the area formed between the curve, which indicates the observed coverage, and the straight diagonal line, which represents perfect equality (CIX = 7.0). ratio between both groups would identify a prevalence twice as high among the richest, whilst an absolute measure of inequality would find that the richest have a coverage that is 20 p.p.…”

Progress Toward Universal Health Coverage

“…We calculated both indices using logistic regression models that take into account the whole population distribution of wealth. 21,27,28 The SII and RII were estimated by regressing health service and financial indicators outcomes against an individual's relative rank in the cumulative distribution of wealth. The SII expresses the absolute difference in coverage in percentage points between the extremes of the wealth distribution (from top to bottom) and gives an idea of the actual effort that will be needed to close the gap.…”

Summary indices for monitoring universal coverage in maternal and child health care

“…The composite coverage index was first proposed in 2008 as the weighted average coverage of eight preventive and curative interventions received along the continuum of maternal and child care. 8,9 The index is calculated at group level, either for a whole country or by subgroups such as wealth quintiles or geographical regions. The co-coverage indicator, proposed in 2005, is a simple count of how many preventive interventions are received by individual motherchild pairs, out of a set of eight interventions.…”