The historical calendar as a method of estimating age: The experience of the Moroccan multi-purpose sample survey of...

Abstract In censuses and surveys in most African countries it has become the practice to estimate informants' age by the method of the historical calendar. This involves an attempt to relate a remembered historical event, occurring during the subject's childhood, with his age at the time. This paper attempts a first evaluation of the method with particular reference to the 1961-63 multi-round survey in rural Morocco. It is shown that in practice the method is highly complex and easily misunderstood by interviewers and respondents. An attempt to lay down a precise procedure by means of a very detailed questionnaire appeared to yield at best only marginally more accurate results than the simpler procedure used in an earlier round. The more complex questionnaire did, however, introduce new patterns of misuse by the interviewer. There was evidence that the historical calendar gave somewhat better data than eye estimates, but results were highly defective for both methods. It is clear that the method is far from perfect. Interviewer training and supervision remain the key to accurate age determination. If the potential benefits of the complex historical calendar method are to be realized, training and supervision need to be even more thorough than where simpler methods are used.