Eight trained investigators (PhD students in Medicine, Pharmacy and Sociology) started out
each day from different points in each town to interview individuals in Wolof, Haalpulaar or
French in every third home, i.e. the dwelling behind every third front door or entrance gate.
Investigators had a certain number of individuals to interview (women aged 20–29 / men aged
20–29 / women aged 30–39 / men aged 30–39 / women aged 40–49 / men aged 40–49 / women
aged 50–59 / men aged 50–59 / women aged 60 and over / men aged 60 and over) to meet the
quotas. Only one person was selected as a respondent in each home. Investigators went to the
house, inquired about the inhabitants and then chose the first person they saw who met the
characteristics needed for the quotas. In-person interviews were conducted. They ranged from
45 minutes to more than 1 hour and 30 minutes, depending on respondent availability and
desire to talk.