If you have a team of six interviewers and each is able to find and interview seven to eight Doers or Non-Doers per day, data for each behaviour can be collected in two days (this does not include the time required to train interviewers, arrange logistics, travel to the target communities, etc.). However, if you are dealing with a less common behaviour or if the travel times are long, more time will be necessary. Since you are likely to want to study two to three key behaviours within a particular project, allocating one week for data collection is a realistic estimate. If your team is too small, ask colleagues from other programmes for help or hire additional interviewers. The main costs you can expect are transport, accommodation, per diems, and external staffs’ remuneration (if required).