Centro Centroamericano de Población of the

Population data in developing countries come mostly from household visits. Armies of interviewers collect those data using paper and pencil (the PAPI method). But that information is infested with nonrandom errors. Newly developed “computer aided personal interviewing” technology (CAPI) is an important advance over PAPI in terms of reducing errors and shortening time lags for data availability. But CAPI has proved to be difficult to implement in developing countries because of the ergonomics, costs, and delinquency restrictions of laptops. In response, we developed a CAPI system for PDAs that may revolutionize the way data is gathered, by reducing fraud, errors and costs and by opening opportunities for collecting complex information. At the core of our PDA-CAPI is an “electronic questionnaire markup language” (EQML) we developed after analyzing thousands of existing questions. This paper reports the lessons learned from using our PDA-CAPI in a complex survey in Costa Rica