Nevill A M, Atkinson G
School of Human Sciences, Liverpool John Moores University, United Kingdom.
Br J Sports Med. 1997 Dec;31(4):314-8. doi: 10.1136/bjsm.31.4.314.
The consensus of opinion suggests that when assessing measurement agreement, the most appropriate statistic to report is the "95% limits of agreement". The precise form that this interval takes depends on whether a positive relation exists between the differences in measurement methods (errors) and the size of the measurements--that is, heteroscedastic errors. If a positive and significant relation exists, the recommended procedure is to report "the ratio limits of agreement" using log transformed measurements. This study assessed the prevalence of heteroscedastic errors when investigating measurement agreement of variables recorded on a ratio scale in sports medicine and sports science.
Measurement agreement (or repeatability) was assessed in 13 studies (providing 23 examples) conducted in the Centre for Sport and Exercise Sciences at Liverpool John Moores University over the past five years.
The correlation between the absolute differences and the mean was positive in all 23 examples (median r = 0.37), eight being significant (P < 0.05). In 21 of 23 examples analysed, the correlation was greater than the equivalent correlation using log transformed measurements (median r = 0.01). Based on a simple meta-analysis, the assumption that no relation exists between the measurement differences and the size of measurement must be rejected (P < 0.001).
When assessing measurement agreement of variables recorded on a ratio scale in sports medicine and sports science, this study (23 examples) provides strong evidence that heteroscedastic errors are the norm. If the correlation between the absolute measurement differences and the means is positive (but not necessarily significant) and greater than the equivalent correlation using log transformed measurements, the authors recommend reporting the "ratio limits of agreement".
舆论共识表明，在评估测量一致性时，最适合报告的统计量是“95%一致性界限”。该区间的确切形式取决于测量方法差异（误差）与测量大小之间是否存在正相关关系，即异方差误差。如果存在正相关且显著的关系，推荐的程序是使用对数转换后的测量值报告“比率一致性界限”。本研究评估了在运动医学和运动科学中研究比率尺度记录变量的测量一致性时异方差误差的普遍性。
对过去五年在利物浦约翰摩尔大学运动与运动科学中心进行的13项研究（提供23个实例）中的测量一致性（或重复性）进行了评估。
在所有23个实例中，绝对差异与均值之间的相关性均为正（中位数r = 0.37），其中8个具有显著性（P < 0.05）。在分析的23个实例中的21个中，该相关性大于使用对数转换测量值时的等效相关性（中位数r = 0.01）。基于简单的荟萃分析，必须拒绝测量差异与测量大小之间不存在关系的假设（P < 0.001）。
在评估运动医学和运动科学中比率尺度记录变量的测量一致性时，本研究（23个实例）提供了有力证据表明异方差误差是常态。如果绝对测量差异与均值之间的相关性为正（但不一定显著）且大于使用对数转换测量值时的等效相关性，作者建议报告“比率一致性界限”。
