Approach	Description
BIA	Undertaking BIA involves following a number of steps: ranking the study population by a living standard measure, assessing the rate of utilisation of different types of health services, estimating the unit cost of each type of service, and multiplying the utilisation rates and unit costs to determine the amount of subsidy. Direct user fees are deducted before arriving at the final amount of government subsidy [15]. The amount of subsidy is usually the difference between the costs incurred for providing the services and the fees paid by the user expressed as:
	Ski = Cki−Fki = cki−fkiqki = qki (cki−fki) = skiqki
	where Ski are the subsidies that individual i receives from subsector k (e.g. hospital inpatient care), Cki are the costs incurred by providers in subsector k in providing services to individual i, Fki are the fees paid by individual i to the provider in subsector k, qki is the number of units of service of type k consumed by individual i, and cki, fki and ski are the unit costs, fees and subsidies, respectively, for sector k for individual i. At the individual level, only Fki and qki are recorded in the household survey data. The goal of BIA is to estimate the distribution of the Ski by income [13].
FIA	A key indicator for measuring the progressivity of a health financing system is the Kakwani index (KI) [63], which is defined as twice the area between the concentration curve of health payments and the Lorenz curve [17]. The KI is calculated as:
	πK = C–G
	where C is the concentration index for health payments and G is the Gini coefficient of the ATP variable. The value of πK ranges from -2 to 1. A negative value indicates a pro-rich or regressive health care payment system. A positive value indicates a progressive financing system with the concentration curve of health care payment lying outside the Lorenz curve. Where health care payment is proportional to ATP, the concentration curve lies on top of the Lorenz curve and the index is zero [12].