在問卷調查的訪員訓練中，訪員均被教導必須避免第三者在場的訪問情境。但是，歐美的研究發現，實際執行的訪問調查不見得能控制百分之百無第三者的在場。不同的研究對第三者在場是否影響訪問結果則尚無一致的結論。不過支持第三者在場對訪問結果有影響者居多，只是影響關係為何仍有待進一步瞭解。至於在台灣執行的訪問調查中，第三者在揚效應的研究至今闕如。因此，本研究企圖比較不同類型問卷題目間是否有第三者在場的訪答效應，並分析此效應會以何種形式存在。

本研究的分析資料來自台灣社會變遷基本調查計畫三期二次卷｜（1996），並從兩個面向一一答題品質與回答結果一一探討訪答效應。 初步的結果發現受訪者在事實性題目的答題品質比其他型題目者好。

Interviewers are trained to conduct private interviews but would find that the presence of others in practice is hard to avoid. Despite of divergent conclusion, most of the previous studies support the importance of the third-person effect. This study examines the extent to which the presence of the third-person affects survey response across three types of questions concerning family, marriage and gender roles respectively Characterized by fact, sensitivity, and social desiribility attributes. 

The data analyzed is from Social Change Survey conducted in 1996. The quality of response to factual questions is found better than that to other types of questions. However, logistic regression analysis shows that the presence of the third-person does not affect the quality of response to three types of questions. On the other hand, the actual response to factual and sensitive questions varies with the presence of the third-person. The third-person effect does not happen to the response to the questions with social desirability.

This study does not fully support the hypotheses that the third-person would affect the quality of response and actual response to sensitive and social desirable questions more than that to factual questions. However, it the findings does not totally reject the third-person effect. In conclusion, theoretical development and empirical studies on the third-person effect are needed in the future.