Harrison Deed E, Holland Burt, Harrison Donald D, Janik Tadeusz J
Department of Statistics, Temple University, Philadelphia, PA, USA.
J Manipulative Physiol Ther. 2002 Feb;25(2):93-8. doi: 10.1067/mmt.2002.121411.
To determine whether the newly derived interclass and intraclass correlation coefficients (ICCs)would overstate or understate the results from 2 previously published studies, which used better known ICCs that assume nested factors, and to determine mean absolute differences of observers' measurements for 3 previous studies.
Retrospective analysis of data from 2 blind studies with repeated-measure design. Two newly derived ICCs, appropriate to situations with 3 random factors (patients, examiners, and occasions) that bear a crossed (as opposed to nested) interrelationship, were applied to data from an experiment with random crossed factors.
Observer reliability is determined with ICCs, 95% CIs, and observer error analysis (mean absolute differences of observers' measurements) for angles and distances derived from Harrison's modified Risser-Ferguson line-drawing method on anteroposterior (AP) lumbar and AP cervical radiographic views. Observer error analysis for angles and distances derived from Harrison's posterior tangent method on lateral cervical views was also determined.
The majority of ICCs for reliability of line drawing on both AP cervical and AP lumbar radiographs were in the high range; 13 of 16 ICCs were greater than 0.88. The other 3 ICC values (0.61, 0.76, 0.78) concerned determining the sacral base on AP lumbar views. The new ICCs underestimated observer reliability compared with previously published results (intraclass ICCs lower by 0.01-0.02 and interclass ICCs lower by 0.03-0.10). For an error analysis on data from both AP views, the mean absolute differences of observers' measurements were 1.1 degrees to 1.8 degrees for angles and 1.2 mm to 2.3 mm for distances. For the lateral cervical analysis, the observer error was in the interval 0.8 degrees to 3.2 degrees for angles and <1 mm for distances.
The ICCs assuming random crossed factors understate reliability compared with previously published ICC results assuming nested factors. Reliability of the Harrison modified Risser-Ferguson method of line-drawing analysis on AP views is in the high range, with the majority of ICCs >0.88. For both the Harrison modified Risser-Ferguson method on AP views and posterior tangent method on lateral cervical views, the mean absolute differences of observers' measurements are small.
确定新推导的组间和组内相关系数（ICC）是否会高估或低估两项先前发表研究的结果，这两项研究使用了更知名的假设嵌套因素的ICC，并确定三项先前研究中观察者测量值的平均绝对差异。
对两项采用重复测量设计的盲法研究数据进行回顾性分析。将两个新推导的ICC应用于具有随机交叉因素的实验数据，这两个ICC适用于具有三个随机因素（患者、检查者和测量时机）且相互交叉（而非嵌套）关系的情况。
通过ICC、95%置信区间以及观察者误差分析（观察者测量值的平均绝对差异）来确定观察者的可靠性，这些指标针对的是在腰椎前后位（AP）和颈椎前后位X线片上采用哈里森改良的里塞尔 - 弗格森线绘制法得出的角度和距离。还确定了在颈椎侧位片上采用哈里森后切线法得出的角度和距离的观察者误差分析结果。
颈椎前后位和腰椎前后位X线片上线条绘制可靠性的大多数ICC处于较高范围；16个ICC中有13个大于0.88。另外3个ICC值（0.61、0.76、0.78）涉及在腰椎前后位片上确定骶骨基部。与先前发表的结果相比，新的ICC低估了观察者的可靠性（组内ICC低0.01 - 0.02，组间ICC低0.03 - 0.10）。对于来自前后位片数据的误差分析，观察者测量值的平均绝对差异对于角度为1.1度至1.8度，对于距离为1.2毫米至2.3毫米。对于颈椎侧位分析，观察者误差对于角度在0.8度至3.2度之间，对于距离小于1毫米。
与先前发表的假设嵌套因素的ICC结果相比，假设随机交叉因素的ICC低估了可靠性。在前后位片上，哈里森改良的里塞尔 - 弗格森线绘制分析方法的可靠性处于较高范围，大多数ICC大于0.88。对于前后位片上的哈里森改良的里塞尔 - 弗格森方法和颈椎侧位片上的后切线方法，观察者测量值的平均绝对差异都很小。
