The efficiency of the multiple trial randomized response technique.

It has been proven theoretically that repeated administration of two-related-question randomized response technique (RRT) substantially increases the efficiency by reducing the variance of the estimate. The realtive efficiency of RRT to direct question with various number of trials per respondent under various degrees of truthful response and various conditions has also been examined. However, if the respondent becomes more concerned about his anonymity, then the mean square error may be larger. A field study of limited scope conducted in Taichung, Taiwan indicated that this multiple trial RRT model is at least as feasible as, if not more feasible than, the conventional single trial RRT. There was no sign suggesting cooperation of respondents had deteriorated because each was asked to repeat the procedures three times. If the number of trials did not exceed three, we believe that the increase in the cost of survey and "exhaustion" of respondents from repeated administration of the same set of questions would be negligible. Hence, we believe that this multiple trial technique is a feasible and useful survey method for study of various contemporary social problems of sensitive nature. More field testing, particularly in different socio-cultural settings, is necessary however, before a general conclusion may be drawn.