Garratt Andrew M
Unit of Health Care Epidemiology, Institute of Health Sciences, University of Oxford, Oxford, United Kingdom.
Spine (Phila Pa 1976). 2003 Jan 1;28(1):79-84. doi: 10.1097/00007632-200301010-00019.
A cross-sectional survey using patient questionnaires was conducted. OBJECTIVE To assess whether the Roland Disability Questionnaire satisfies the Rasch model including unidimensionality and item separation.
The Roland Disability Questionnaire, the most widely used patient-assessed measure of health outcome for back pain, has undergone several evaluations for its measurement properties including reliability, validity, and responsiveness. However, there is no published work relating to the underlying dimensionality of the instrument and the extent to which individual items contribute to the construct of physical disability resulting from low back pain.
Patients entering a randomized controlled trial of exercise, manipulation, and usual management for back pain completed a questionnaire that included the Roland Disability Questionnaire. The Winsteps program was used to assess whether the Roland Disability Questionnaire fits the Rasch model. Item fit was assessed using the Infit and Outfit statistics.
The Roland Disability Questionnaire was completed by 1008 (90%) of the patients taking part in the trial. Most of the items in the Roland Disability Questionnaire contribute to a single underlying construct. However, four items had poor Outfit statistics, suggesting that they do not contribute sufficiently to the scale hierarchy. Several items positioned around the middle of the hierarchy are not sufficiently distinct in terms of difficulty. There were very few items positioned at the extremes of the hierarchy.
The Roland Disability Questionnaire largely satisfies the Rasch model for unidimensionality. However, the instrument could be improved through the removal of poorly fitting items and the addition of items at the upper and lower points of the scale hierarchy. The distribution of Roland Disability Questionnaire scores should be carefully considered before statistical testing is undertaken. Rasch transformed scores can be used to deal with deficiencies in the scale hierarchy.
采用患者问卷进行横断面调查。目的是评估罗兰残疾问卷是否符合拉施模型，包括单维性和项目区分度。
罗兰残疾问卷是用于评估背痛患者健康结局的最广泛使用的患者自评工具，其测量特性，包括信度、效度和反应度，已经过多次评估。然而，关于该工具的潜在维度以及各个项目对腰痛导致的身体残疾结构的贡献程度，尚无已发表的研究。
参加运动、手法治疗和常规腰痛管理随机对照试验的患者完成了一份包含罗兰残疾问卷的问卷。使用Winsteps程序评估罗兰残疾问卷是否符合拉施模型。使用拟合度和拟合优度统计量评估项目拟合情况。
参与试验的患者中有1008名（90%）完成了罗兰残疾问卷。罗兰残疾问卷中的大多数项目都有助于单一的潜在结构。然而，有四个项目的拟合优度统计量较差，表明它们对量表层次结构的贡献不足。位于层次结构中间位置的几个项目在难度方面不够明显。位于层次结构两端的项目很少。
罗兰残疾问卷在很大程度上符合单维性的拉施模型。然而，该工具可以通过删除拟合不佳的项目以及在量表层次结构的上下两端添加项目来改进。在进行统计测试之前，应仔细考虑罗兰残疾问卷分数的分布。拉施转换分数可用于处理量表层次结构中的缺陷。
