Responsiveness
Responsiveness demonstrates whether a questionnaire can be used to
identify changes over time 5,9–11, assessing the
interpretability of those changes 5,10,11.
Responsiveness is supported when a measure can identify differences in
results, even if these differences are small. Methods of assessing
responsiveness include comparing instrument scores before and after an
intervention. Specific disease measures are more sensitive to small
changes in disease status and are generally considered to be more
sensitive than generic measures 9. Responsiveness can
be evaluated by longitudinal analyses of patients, and some used
measures of responsiveness are the standardized response mean (SRM), and
the effect size (ES). The SRM is calculated by dividing the mean score
change by the standard deviation of the change; and the ES is the degree
of change measured in standard deviations 5,12.
Responsiveness is occasionally referred to as sensitivity to change, but
although they are related, they are different. Responsiveness is the
ability of the instrument to measure important clinical changes among
patients, whereas sensitivity to change refers to the ability of the
instrument to detect any degree of change 5.