To accomplish our research objectives, we collected data from Tax auditor of Thailand. A mail survey was used for data collection. The questionnaire was sent to 500 tax auditors. The questionnaires have been shown in previous research to be knowledgeable key informants about information concerning strategic audit planning. With regard to the questionnaire mailing, 11 surveys were undeliverable because some tax auditors were moved to the unknow address. Deducting the undeliverable from the original 500 mailed, the valid mailings were 489 surveys, from which 154 respondents were received. The effective response rate was approximately 31.49%. According to Aaker, Kumar and Day (2001), the response rate for a mail survey, without an appropriate follow-up procedure, is less than 20%. Then, the response rate of this study is considered acceptable. The average auditing experience was over nine years old. The average revenue per month was more than 60,000 baht.