PCA based on asset ownership and average weekly food expenditure was preferred to the use of income because Nigeria still has a huge informal sector whose monthly or annual income might be difficult to measure and food expenditure consumes more than 50% of the income of most families [ 15].
Cost-effectiveness was analysed on the basis of incremental net monetary benefit, which was based on quality-adjusted life-years (calculated using EQ-5D scores), and all medication expenditures consumed in 1 year.
e is the household food expenditure, f is the household expenditure for food consumed away from home (meals and beverages) and Z i j denotes the j th of n household characteristics.
This 'Multi-Purpose Survey' (MPS) included detailed information on the demographic and social characteristics of households, their economic activities and housing conditions in addition to detailed figures on households' earnings, expenditures and quantities consumed of food and non-food items.
Third, the absence of detailed figures on food expenditures and quantities consumed at the individual level in the survey may hide interesting and important aspects of malnutrition in the country.
In the literature, there are two main methods for retrieving price data from expenditure and quantity variables: using unit values as proxy for market prices, as Abdulai ([2002]) or Akbay et al. ([2007]) did by dividing the expenditure by the quantity consumed.
In the three counties: a small proportion of women received the number of haemoglobin and urine tests recommended by the national guideline; 90% of women received more ultrasound tests than recommended; and the out-of-pocket expenditure for prenatal care consumed a high proportion of women's annual income in the low income group.
For example, in the United States currently, the top 1% of healthcare consumers consume 20.2% of all system healthcare expenditures and the top 15% consume 73.4% of all expenditures [ 59].
Furthermore, x denotes income and x2 the square of income, e is the household total expenditure for beverages, and f is the household total expenditure for food and beverages consumed away from home.
Therefore, an indirect method using unit values (total expenditure divided by total quantity consumed) of each tobacco product is used.
