There are two main options for collecting household expenditure data:
A) THE RECALL APPROACH
During the recall approach, respondents are asked to report how much they spent on different categories of consumption goods and services in a certain period. It involves the following steps:
1) Define the recall period – i.e. the time period for which respondents are asked to report their household's consumption (it is recommended to use a maximum of 7 days recall period).
2) Define the reference period – i.e. the period your survey aims to assess (for example, expenditures during the past 3 weeks - in such a case, you will have to interview the respondent 3 times, every 8th, 15th and 22nd day – always using a 7-day recall period).
3) Define different expenditure categories – it is recommended to use four main types of categories: i) food items (any types of purchased food and drinks); ii) non-food items and services (any types of frequently purchased items/ services, including health and education-related expenses); iii) consumer durables (usually more expensive items that are used over an extended period of time, such as mobile phone or cooking stove); iv) housing (rent, utilities, repairs).
4) Prepare a questionnaire enquiring about households' expenditures - see an example of one part of the questionnaire:
i) Food items
Q1: In the past 7 days, how much money did your household spend on purchasing food (not in the restaurants)?
Q2: In the past 7 days, how much money did your household spend on purchasing any types of drinks (not in the restaurants)?
Q3: In the past 7 days, how much money did your household spend on purchasing food and drinks in the food stalls/ restaurants/ bars?
5) Interview the respondents.
6) Calculate the indicator's value by summing up the expenditures of all surveyed households and dividing them by the total number of households.
B) THE DIARY APPROACH
In the diary approach, respondents are asked to keep a diary over a certain period of time in which they record every single expense (= the approach is suitable for literate respondents only). This approach is often viewed as more precise as it involves a lower risk of people forgetting the different expenses they made during the recall period; on the other hand, people often forget or are not motivated to record their expenses. It involves the following steps:
1) Define the reference period – the longer the period you use, the more likely it is that people will regularly stop (or completely) recording their expenses; a maximum of 2 weeks reference period is recommended.
2) Prepare a simple, easy-to-use recording form whose rows list all the different expenses and the columns list specific dates; do not use the form before you pre-test it and you are sure that the respondents can use it well.
3) Explain to the respondents how to use the form, fill out the previous (= first) day with them and request them to use it for the duration of the reference period (consider proposing an incentive where those respondents who regularly (daily) fill the form will, at the end of the survey, receive a payment; respondents' compliance must be controlled through spot-check visits).
4) Calculate the indicator's value by summing up the expenditures of all surveyed households and dividing them by the total number of households.