The use of anthropological qualitative methods to validate and improve health surveillance data is demonstrated through an examination of the process of birth registration in Gaza. Theoretically, the importance of understanding the link between historical events and microlevel decision-making is emphasized both in general terms and specifically in the context of the Gaza Strip today. In the course of interviewing a sample of mother/infant pairs selected from a register of births in the Gaza Strip it became evident that 100% of the addresses were incomplete. Using qualitative methods in the form of field visits and interviews with physicians, clerks and nurses, an understanding of the information pathway for birth registration data was developed. It was also established that there was some erroneous recording of birthweight. An intervention was designed which failed to improve the accuracy of addresses but did improve the recording of birthweight.