7 whenever information is available so as to avoid including people living in households using one or two solar lanterns. In countries where survey questionnaires asked only about solar energy (Botswana, Burkina Faso, Ethiopia, Ghana, Senegal, South Africa, Swaziland, Togo, and Uganda), definition 4 could well over‐estimate the number of people with access, if households with solar lanterns had replied that they were using solar energy for lighting.

All surveys asked about spending on electricity, most commonly in the last 30 days. There are limitations with this approach. Payment arrears may be common, but no household surveys in this paper probed this point. By contrast, the 2012 National Survey of Household Income and Expenditures in Mexico asked a series of questions to understand arrears, including when the last payment for electricity had been made, while the 2005 Integrated Sample Household Budget and Labor Survey in the Kyrgyz Republic asked for kWh of electricity consumed, the amount billed, and the amount paid for three successive months as well as the amount of subsidy received. Most household surveys, however, simply ask how much the household paid last month for electricity. Asking just one question about how much the household paid over a fixed period of time could under‐ or over‐estimate (the latter if past debts are being repaid to utilities) monthly expenditures on electricity. Cross‐checking household survey data against data from the utilities could indicate the magnitude of these problems and ways of adjusting data for a more accurate picture. Lampietti and Junge (2006) combined billing and payment records from the utility and merged them with household survey data to address recall errors, under‐ and over‐reporting, and the presence of arrears, which enabled more accurate estimation of current and historical electricity consumption as a function of household income and other characteristics. However, obtaining utility data for such cross‐checking was outside the scope of the study.

The survey in Senegal asked if the household had spent anything on electricity over the last 12 months, which would more likely capture whether the household was paying something for electricity. If the question is about spending only in the last month only, no payment might have been made for a variety of reasons and the household would be registered as having zero expenditure. Similarly, some households did not answer the question (they might have found it difficult to recall the amount in the short time given to answer this question during the interview), and all missing responses were recorded as zero in the analysis. In all 22 countries, not all who cited electricity as the primary source of energy for lighting reported positive expenditures in electricity. Legitimate reasons for having no expenditures for grid electricity, the focus of this study, include electricity included as part of the rent, bundling of utility services (such as combined water and electricity bills), or free electricity being part of the compensation package for employment. It is also possible that the household happened not to have made payments during the recall period—for example, the household could have missed one bill payment, making up for it later.

Examination of spending on electricity was necessarily confined to those who reported positive expenditures on electricity. Among those who did, spending on electricity was computed as a share of total household expenditures as one measure of affordability. Because power tariffs in many countries are pan‐territorial and do not have large regional differences that are observed with food and other items, nominal expenditures on electricity and nominal total household expenditures were used to compute expenditure shares, except in Angola and Mozambique where nominal expenditures were not available and where regionally adjusted expenditures were used.

Where enough information was available on how consumption aggregates were derived for official poverty statistics, expenditures on food were disaggregated into those paid for by cash and freely acquired food that had been assigned imputed values. The purpose of doing so was to estimate the total amount of cash