李克式量表標示語之心理量尺值研究

Estimating Scale Values of Response Anchors in Likert-type Scales

社會科學和心理學研究經常以問卷或量表方式收集受試者在各題目的反應資料。李克式量尺則為此類研究收集資料時問卷或是量表常用的方法，而量表標示語的心理量尺值在資料的分析和解讀上有重要意涵，但標示語所真實表徵的心理量尺值有不同的估計方法，也未有明確公認的結論。過往研究曾以連續區間法、簡化連續區間法、歸等測驗和自由反應測驗等方法探討量尺標示語由不同估計法所得之心理量尺值的差異。本研究採用配對比較評量、單一直接評量，以及同時排序評量等三種方法對同意、符合及頻率三類標示語進行量尺值估計。本研究針對各個度量法方法所估計之心理量尺值進行分析比較，並探究量表標示語之間的相對關係、對稱性，以及語詞結構對量尺估計值的影響。文中並綜合討論三個量尺值估計法所得結果之差異及其影響，文末提出本研究結果於實徵應用研究的可能貢獻，並對實徵應用研究使用李克式量尺時在標示語選擇上的具體建議。

Social science and psychological research often uses question¬naires or scales to collect data. Likert-type scales are the most com¬monly used scales in questionnaires or scales when collecting data. The psychological scale values of the scale labels/descriptors/anchors have important implications in the analysis and interpretation of data. Differ¬ent methods and formats have been proposed for estimating the scale values of a Likert-type scale. Previous studies have used successive interval and simplified successive interval estimation methods. Studies have also used an open-response format and category-level assigning format to study the scale values. However, there is no consensus and still a lack of studies comparing different estimation methods. In this study, three estimation methods of label scale values are investigated: the paired-comparison method, direct rating method, and simultaneous ranking evaluation method. Three common types of scale labels are investigated in this study: agreement-, conformity-, and frequency-type. A review on the usages of Likert scale labels in literature was con¬ducted, 24 agreement-type labels, 24 conformity-type labels, and 20 frequency-type labels were included in this study. There were 97 sub¬jects (27 males and 70 females) who participated in this study. The mean age of the subjects is 20.68 years old with a SD of 1.54. The sub¬jects took part in lab experiments with three tasks. In the direct rating task, subjects used a mouse to drag a marker on a horizontal bar to indicate the rating of a given label stimulus. In the pair-comparison task, subjects used the mouse to drag a marker on a horizontal bar to indicate the degree of difference of a given pair of labels. In the simul¬taneous ranking evaluation task, subjects were presented with all the labels on the top panel of the screen and the subjects’ task was to drag these labels in any order they preferred to any location on the horizontal bar located in the center of the screen. Subjects could adjust the location of any label on the horizontal bar before they clicked the “confirm” button to submit their answer. Subjects’ responses to the three tasks were recorded on a 0-1000 scale for further analysis. The collected data were analyzed and compared the psychological scale values estimated by the three estimation methods. The results suggested the equal space assumption between points on the Likert scale is in general not hold based on the estimated scale values of this study. The results also sug¬gested substantial differences among the three estimation methods. Moreover, the estimated scale values of the selected labels were also not evenly distributed on the evaluation scale; more labels were loaded toward the extreme portion of the scale. The possible explanations for this observation are discussed in the discussion section. Since it is dif¬ficult to locate appropriate labels based on the estimated psychological scale values on a Likert-type scale, we suggested using only the “end-label” on a Likert scale in practice, for example, “completely disagree- completely agree” and “never-always” as the labels on a Likert-type scale. The limitations of the present study were presented in the discus¬sion section as well as references for further reading on these topics. Other psychometric methods such as item-response theory (IRT) and Fuzzy Linguistic/numbers approach for dealing with Likert-type scale labels were also discussed in the concluding remarks.