本文應用一個澎湖遊客問春調查的資料做爲研究樣本，檢臉先覆函者與後覆函者在進客特性、旅進環境知覺與消費行爲上之差異。研究結果顯示先覆函者與後覆函者之間並無明顯差異。此外，本文亦探討均質團體中在延遲回覆對非覆函偏誤之影響。在控制遊客均質性之後，檢驗先後覆函者間之差異，結果發現兩群體問並無顯著差異。本文提示在研究離島旅進行爲時，使用均質性高的道客爲研究樣本時，郵寄問卷調查中非覆函偏誤之影響。

Using data from a Pescadores' visitor mailed questionnaire survey,the article examines the difference between early and late respondents in terms of characteristics, perception, and expenditure. Results indicate that no significant differences were uncovered between two group respondents. Also, this study examines whether survey results profiling homogeneous visitor population can be valid at lower response rate. Comparisons were conducted and results reveal that data on late respondents do not differ from data on early respondents. The result provide some empirical clues to understanding the conditions under which population homogeneity exists.