Association of Dutch Burn Centers, Beverwijk, The Netherlands.
Qual Life Res. 2012 Feb;21(1):13-23. doi: 10.1007/s11136-011-9924-5. Epub 2011 May 20.
The Patient and Observer Scar Assessment Scale (POSAS) is a questionnaire that was developed to assess scar quality. It consists of two separate six-item scales (Observer Scale and Patient Scale), both of which are scored on a 10-point rating scale. After many years of experience with this scale in burn scar assessment, it is appropriate to examine its psychometric properties using Rasch analysis.
Cross-sectional data collection from seven clinical trials resulted in a data set of 1,629 observer scores and 1,427 patient scores of burn scars. We examined the person-item map, item fit statistics, reliability, response category ordering, and dimensionality of the POSAS.
The POSAS showed an adequate fit to the Rasch model, except for the item surface area. Person reliability of the Observer Scale and Patient Scale was 0.82 and 0.77, respectively. Dimensionality analysis revealed that the unexplained variance by the first contrast of both scales was 1.7 units. Spearman correlation between the Observer Scale Rasch measure and the overall opinion of the clinician was 0.75.
The Rasch model demonstrated that the POSAS is a reliable and valid scale that measures the single-construct scar quality.
患者和观察者瘢痕评估量表（POSAS）是一种用于评估瘢痕质量的问卷。它由两个独立的六分量表（观察者量表和患者量表）组成，两者均采用 10 分制评分。在烧伤瘢痕评估中使用该量表多年后，使用 Rasch 分析检查其心理计量学特性是恰当的。
来自 7 项临床试验的横断面数据收集产生了 1629 份观察者评分和 1427 份患者评分的烧伤瘢痕数据集。我们检查了 POSAS 的个体-项目映射、项目拟合统计、可靠性、反应类别排序和维度。
POSAS 与 Rasch 模型拟合良好，但表面积项目除外。观察者量表和患者量表的个体可靠性分别为 0.82 和 0.77。维度分析显示，两个量表的第一个对比解释的方差为 1.7 个单位。观察者量表 Rasch 测量值与临床医生整体意见的斯皮尔曼相关性为 0.75。
Rasch 模型表明，POSAS 是一种可靠和有效的量表，可测量单一结构的瘢痕质量。
