Siempre Salud trains surveyors using didactic and practical sessions, mentoring, and supervised experience. The didactic session is brief (showing the class how to complete a census form). Then we (the teachers) act as simulated heads of households as the class, each student in turn, asks survey questions. Then we form the class into pairs. One student of each pair is given a set of simulated families and acts as head of household. The other member of each pair acts as surveyor and completes census forms. Then each pair of students exchanges roles using another set of simulated families. As class progresses we hand out identification cards in three different colors: green cards, white cards, and red cards indicating outstanding ability, satisfactory ability, and inability to function alone. The significance of the colors is unknown to the students of course. We match “green card” students with “red card” students whom we ask to work as a pair during the census. The reasons for “red cards” include vision and reading problems and difficulty following a map (abstract reasoning). The result of the “red card-green card” mentoring system is that many of our “red card” students have become our most productive and accurate surveyors.