2002 年 29 巻 1 号 p. 81-89
The Asahi Shimbun telephone survey made the transition from the list-assisted method to ASAHI-RDD (Random Digit Dialing) method in its survey prior to the Upper House Election in July, 2001. In fact, the Asahi Shimbun had estimated that more seats would be taken by the LDP than the actual results showed in the Upper House election in 1998 and in the Lower House election 2000, where they were without a win. The most probable cause of past failures consists of the non-coverage error since the list-assisted method had serious faults due to the large unlisted population. As RDD promised to give better results, Asahi decided to make use of Random Digit Dialing. While the Asahi method consists of Bank2 and random sampling, it does not use quota sampling. Its bank2-map includes the data, the number of listed-households and the overlap rate of area. A time schedule is created arranging the number of interviewers according to each day of the week. In addition to the problems caused by the current widespread use of mobile phones, there are many other problem areas which we must investigate and make efforts to solve.