Agreement & responsiveness
Allows to calculate various indices for responsiveness, which is the ability to detect any change.
- 1st and 2nd measurement: the variables for a 1st and 2nd measurement.
- Filter: an optional filter to include only a selected subgroup of subjects (rows).
- Paired data: select this option when the variables for 1st and 2nd measurements contain paired data (measurements are repeated on the same subjects). If the 2 measurements are independent, unselect this option.
- Calculate differences as: option to calculate differences as 1st minus 2nd measurement (default is 2nd minus 1st).
- Advanced: the confidence intervals for the different indices of responsiveness are estimated using the bias-corrected and accelerated (BCa) bootstrap (Efron, 1987; Efron & Tibshirani, 1993). Click bootstrapping options such as number of replications and random-number seed. for
- The sample size, mean, variance and standard deviation of the 1st and 2nd measurement.
- The average difference between the two measurements with the pooled standard deviation and (in case of paired observations) the standard deviation of the paired differences.
Indices of responsiveness
- Effect size (ES) using baseline SD: this is the average difference divided by the standard deviation of the 1st measurement (this is Glass' Δ).
- Effect size (ES) using pooled SD: this is the average difference divided by the pooled standard deviation of both measurements (this is Cohen's d).
- Standardized response mean (SRM): this is the average difference divided by the standard deviation of the differences between the paired measurements.
- Efron B (1987) Better Bootstrap Confidence Intervals. Journal of the American Statistical Association 82:171-185.
- Efron B, Tibshirani RJ (1993) An introduction to the Bootstrap. Chapman & Hall/CRC.
- Husted JA, Cook RJ, Farewell VT, Gladman DD (2000) Methods for assessing responsiveness: a critical review and recommendations. Journal of Clinical Epidemiology 53:459-168.
- Norman GR, Wyrwich KW, Patrick DL (2007) The mathematical relationship among different forms of responsiveness coefficients. Quality of Life Research 16:815-822.