Department of Psychology, Marquette University, P.O. Box 1881, Milwaukee, WI, 53201-1881, USA.
Qual Life Res. 2019 Mar;28(3):841-853. doi: 10.1007/s11136-018-2064-4. Epub 2018 Nov 27.
The goal of this study is to compare three different types of retrospective frequency response formats on the Healthy Days Symptoms Module (HDSM). Responses are compared in terms of intra-individual consistency, psychometric value, and participant feedback about each type of response format.
Respondents each completed three versions of the HDSM, where items were framed to elicit an open-ended frequency, a fixed choice frequency, or a vague quantifier response. Traditional reliability statistics were used to evaluate intra-individual consistency. Differential item functioning (DIF) was used to test for response format effects, and item response theory (IRT) scale scores and standard errors were computed across the three forms to compare psychometric value. Linear mixed modeling was used to examine the associations of IRT scale scores across response formats with respondent characteristics.
People are largely consistent in how they respond to items about their health, regardless of the response format, and no DIF was detected between response formats. The IRT scores computed from the "# of days" frequency response formats tend to have better measurement precision than those from vague quantifiers. Open-ended frequencies capture a greater span of individual differences for people reporting fewer symptoms; however, little measurement precision is lost in collapsing the frequencies into categories.
Both the open-ended and fixed choice frequency response formats offer more measurement precision than vague quantifiers. While the open-ended frequency response format may capture more individual differences, respondents tend to report more difficulty with exact frequency recall, and thus, prefer the fixed choice frequency format.
本研究旨在比较健康日症状模块（HDSM）中三种不同类型的回顾性频率反应格式。通过个体内一致性、心理测量值和参与者对每种反应格式的反馈来比较反应。
受访者每人完成了 HDSM 的三个版本，其中项目的表述方式分别为开放式频率、固定选择频率或模糊量词。传统的可靠性统计数据用于评估个体内一致性。差异项目功能（DIF）用于测试反应格式的影响，并且在三种形式上计算了项目反应理论（IRT）量表分数和标准误差，以比较心理测量值。线性混合模型用于研究跨反应格式的 IRT 量表分数与受访者特征之间的关联。
无论反应格式如何，人们在回答有关其健康的项目时都在很大程度上保持一致，并且没有检测到反应格式之间的 DIF。从“# of days”频率反应格式计算出的 IRT 分数往往比模糊量词具有更好的测量精度。开放式频率能够更好地捕捉报告症状较少的个体之间的差异范围；然而，将频率分类为类别并不会导致测量精度的显著损失。
开放式和固定选择频率反应格式都比模糊量词提供了更高的测量精度。虽然开放式频率反应格式可能会捕捉到更多的个体差异，但受访者往往更难以准确回忆频率，因此更喜欢固定选择频率格式。
