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共有 2 篇符合條件的文章
鄭夙芬,政治大學選舉研究中心助理研究員。
Survey Participation in Taiwan: Evidence from the ESC Surveys (in English)(解析台灣的調查參與問題-以政治大學選舉研究中心的調查為例) 文章下載
* 本篇電子檔下載次數:10
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The purpose of this paper is to demonstrate the outcomes of surveys throughout the past decade, as well as to evaluate the survey process. The results of this evaluation will be helpful for developing better research designs and methods in order to continue advancement in the field of survey implementation.

The outcome rate in ESC surveys indicates that people in Taiwan are reluctant to comply with interview requests and tend to decline to be interviewed- response rates remained below the 40% mark for the entire decade. Increasing the contact rate did not result in more cooperation from respondents, as the response rate actually fell over the same time period. In addition, refusal rates increased significantly. Also notable is that among the six categories of reasons for failure, the proportion of refusals has increased, while other failures have decreased as a consequence of ESC's efforts to improve fieldwork methods. The data also indicate that males, young people (under the age of 40), and people with lower levels of education (without senior high school degree) were under-counted in almost every ESC survey.

Results of a short questionnaire administered to respondents in the refusal samples of the 2000 ISVB survey show that it is possible that some people were still afraid to express their political beliefs in Taiwan. The results also indicate that participants and non-participants differed in age, education, ethnicity, party preference and unification- independence stance.

本文的主要目的,在於呈現政治大學選舉研究中心過去十年來在台灣所進行的調查結果,同時也將對調查程序進行評估,以有助於發展改進調查執行程序之研究設計及方法。
對調查結果的分析發現台灣民眾對於訪問的要求愈來愈傾向拒絕受訪,過去十年來的訪問成功率都在四成以下,接觸率的增加並未提高合作率,合作率實際上是在下 降之中,而拒訪率則有顯著增加的情況。在訪問失敗的六個原因之中,大部份都因政大選舉研究中心在訪問方法上的努力而得到改進,但拒訪率仍有明顯的增加趨 勢。資料顯示:男性、四十歲以下,以及高中以下教育程度的民眾接受訪問的比率偏低。
2000年一項對於拒絕受訪者的短問卷調查結果顯示:在台灣可能仍然有許多人不願意表達自己的政治主張,而拒絕受訪者和願意接受訪問者,在年齡、教育程度、省籍、政黨偏好及統獨立場上,都有顯著的差異。
劉從葦,國立中正大學政治學系助理教授
陳光輝,加州大學聖塔芭芭拉分校政治學系博士候選人
Is Weighting a Routine or Something that Needs to be Justified? (in English)(抽樣調查資料之加權:正當的處理方法或是一種迷思?) 文章下載
* 本篇電子檔下載次數:28
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Survey research as a method of collecting sample data is supposed to produce sample statistics which can estimate the corresponding population parameters if the sampling design is appropriate. However, for reasons such as unit non-response, survey data is usually weighted by the institutes that collect the data or by researchers who analyse the data in order to correct or diminish the discrepancies between sample and population. Sample statistics based on weighted data are more representative of the population parameters than unweighted data in terms of some demographic characteristics.Therefore, to some extent, it seems legitimate to weight data and this manipulation has become a routine when dealing with survey data.

It is true that to weight data could be helpful, but this manipulation needs justifications. This paper therefore tries to argue that to weight data is no panacea and should not be taken for granted when considering the examples in Taiwan’s Election and Democratization Studies (TEDS) surveys. The first section discusses why weighted data is not necessarily representative of the population. As the TEDS surveys show, the turnout, the vote shares of parties, and marital status become more deviant from the population parameters after weighting the data.

If the focus is the relationships between variables, the correlations may be changed by weighting the data in bivariate or multivariate analysis. However, it is not clear whether we manufacture relationships which do not exist or if weighting the data actually helps us approximate the relationships that already exist in the population. Besides, it should be noted that to weight data set as a whole only deals with the problem of unit non-response, but does not solve the problem of item non-response.

The third section discusses why most efforts should be devoted to examining and improving questionnaires, sampling designs, and interviewerm straining and supervision, instead of simply appealing to post-weighting. If everything necessary has been tried, weighting data may be the last resort to improve the estimates. But the justifications for the selection of auxiliary variables and the methods of calculating weight factors should be provided rather than doing it without any explicit considerations. It is also important to consider whether the consequence of weighting is positive or negative.

經由抽樣設計恰當的調查研究所收集到的樣本資料應該能夠準確估計母體參數。但是因為單位無反應的問題,執行調查的單位或分析資料的學者通常會以加權的方式來 減少樣本統計量與母體參數之間的差距。加權後的資料在人口學變項上比未加權資料較為接近母體參數,因此加權似乎是一個合理處理樣本資料的做法。

然而,即使加權是可行的解決方法,也絕非萬靈丹。在加權前也必需提出事後操弄資料的理由,而不是將加權視為理所當然。本文以台灣選舉與民主化調查為例,首 先說明加權後的資料不必然較接近母體參數的原因。投票率、各政黨得票率、與婚姻狀況在加權後反而和母體參數有較大的差距。

除了單一變數分析之外,當討論的主題是變數間的關係時,加權可能增加也可能減少相關性的強度。雖然加權似乎會影響相關性,但其影響究竟是更接近真實的關 係,抑或是扭曲真正的相關性則不得而知。此外,通常對整筆資料作加權只處理了單元無反應的問題,但仍然沒有解決多變量分析一定會遇到的項目無反應問題。

不論是單一變數分析或是多變量分析,在加權之前應該先嘗試其他增加樣本代表性與提高資料品質的方法。如果沒有先投入更多時間與心力在問卷設計、抽樣設計、 訪員訓練與監督上,加權只是低成本的取巧做法。最後,假使一定要加權,必須說明與討論為什麼要加權、以哪些變數加權、如何加權、以及加權所產生的影響,而 非不加思考地將加權當作例行公事。