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Table 1 Summary of equations used in agreement analysis

From: Reproducibility: reliability and agreement parameters of the Revised Short McGill Pain Questionnaire Version-2 for use in patients with musculoskeletal shoulder pain

Equation Formula Purpose
1 SDpooled = (SDtest + SDretest)/2 For estimating pooled standard deviation (SDpooled) from the test and retest scores. The SDpooled is among the indices required for SEMagreement estimation
2 SEMagreement = Standard Deviationpooled ×\(\sqrt{1}-\mathrm{ICC}\) 2,1 For estimating SEMagreement, which is important for the MDC90individual estimation
3 MDC90individual = 1.64 × √2 × SEMagreement For determining the point estimate of MDC90individual, which is required for estimating the confidence interval range and the MDC90group scores per subscale of the SF-MPQ-2
4 95% CI for MDC90individual = d ± MDC90individual For computing the 90% confidence interval range for the MDC90individual score obtained for each subscale of SF-MPQ-2
5 MDC90group = MDC90individual /√n × 1.64 For estimating the MDC90 group score for the entire population
  1. SEMagreement standard error of measurement (agreement), SDtest standard deviation of test scores, SDretest standard deviation of retest scores, SDpooled pooled standard deviation, n sample size, CI confidence interval, MDC90individual individual level minimal detectable change at 90% CI, MDC90group group level minimal detectable change at 90% CI, d mean difference, ICC2,1 intraclass correlation coefficient