In a readership survey conducted in London, one interview in every three had been tape recorded. Through follow-up intensive interviews, conducted the next day, estimates were developed of the accuracy of certain of the information collected in the first interview. This situation provided an opportunity to compare: a. the estimated accuracy of information collected in the readership survey when a tape recorder was used with b. the estimated accuracy of such information when a tape recorder was not used. The recorded and the non-recorded samples were closely matched, on an empirical basis, in order to increase the meaningfulness of the comparison of (estimated) accuracy with and without the recorder being used. The comparison made here is of 189 recorded estimates (from 105 people) and of 430 non-recorded estimates (from 226 people). The small numbers involved make this a small-scale study, so that its results must be regarded as indicative and not final.