Problems of Contamination in Panel Surveys: A Brief Report on an Independent Sample, Taiwan, 1970

To check the possibility of data contamination through reinterview effects interviews of an independent sample of 500 women were compared to interviews of 2600 women who had been interviewed in 1967 and again reinterviewed in 1970. Both KAP samples found 3.9 to be the ideal number of children and 2.2 for the ideal number of sons. 95% of both groups approved of birth control much or very much. The differences found in the 2 groups were in the knowledge and use of contraception. The reinterviewed women knew of contraceptive methods more often than the independent sample which may be a result of reinterviewing effects on the level of information. The extent of contraceptive use is similar in the 2 samples except for women over 35 where the reinterviewed women were more likely to have used an IUD. The overall conclusion is that reinterviewing contaminations are minimal and thus panel studies probably do not condition the respondents replies on critical variables.