Lack of explicit criteria in identifying the household head impacts the adequacy of poverty statistics for female- and male-headed households. The traditional notion of head of household assumes that one person has primary authority and responsibility for household affairs and is, in the majority of cases, its chief economic support. However, where spouses are considered equal in household authority and responsibility and may share economic support, the concept of head of household is no longer considered valid. In those countries, the concept should not be used anymore, or provisions for joint headship should be made. Even in the many countries where the traditional concept of head of household is still relevant, it is important to recognize that the procedures followed in applying it may distort the true picture, particularly with regard to female heads of households. The most common assumption that can skew the facts is that no woman can be the head of any household that also contains an adult male. This fact is often neglected, resulting in biased interpretation of the association between gender and poverty.
Use of different criteria in defining the household headship leads to the identification of different sets of households with different poverty rates (Fuwa, 2000). The criteria used to identify a household head should be clearly specified in the survey design, so that they are the same for all households surveyed. Depending on the criteria selected, the identification of the head can be done at the time of the interview or at the analysis stage. For example, head of the household may be defined, at the time of the interview, as the person considered by the household members as the main economic provider with most authority and decision-making power on economic resources. Or, at the analysis stage, the head of the household may be defined as the person with the highest income or the person with regular stable income. Analysis of poverty differences between female-headed households and male-headed households based on self-reporting should be avoided when the respondents interviewed were not given any criteria in identifying the head.
The current practice of disaggregation of household-level poverty data by sex of the household members gives only a poor measure of gender gap in poverty. Poverty is traditionally measured based on income or expenditure at the household level, and the number of poor (women or men) is calculated as the number of people living in households found below a poverty line. The inequality within the household in satisfying individual basic needs is not taken into account, mainly because it is difficult to measure how household income is spent or consumed on an individual basis or how expenditures are distributed to each household member. The results of disaggregation of household-level poverty data by sex of the household members are not going to reflect possible gender inequality within the households but merely the distribution of population by sex in poor households. If in the same household women consume or spend less than what they need to function properly physically and socially (therefore poor), while men consume or spend what they need or more (therefore non-poor), those women and men in the household are still considered to have the same poverty status, either poor or non-poor, depending on the average consumption estimated at the household level. This approach may lead to undercounting of women in poverty because additional poor women might be found in some non-poor households.
In addition, the gender gap measured based on simple poverty counts by sex is heavily influenced by country-specific living arrangements and ageing factors (United Nations, 2010). Poverty rates for women may appear higher than poverty rates for men especially in countries with significant proportions of households with overrepresentation of adult women, such as households of lone mothers with young children and female one-person households, particularly one-person households of older women. These countries are more likely to be located in the more developed regions, where, by other standards of wellbeing, such as education or health, women enjoy an improved status and less gender discrimination.