The minimal clinically important difference for the Gait Profile Score.

The minimally clinically important difference (MCID) is an important concept for interpreting the results of clinical research. This paper proposes a rationale for defining an MCID for the Gait Profile Score (GPS) based on an analysis of the difference in median GPS for children classified at different levels of the Functional Assessment Questionnaire. A strong linear correlation between median score and FAQ level was found. An MCID of 1.6° is therefore suggested, reflecting the mean difference between adjacent FAQ levels. Comparison of this value with (i) the standard deviation of GPS from typically developing children (1.4°) and (ii) the percentage of the difference between the median GPS for each FAQ level and that for typically developing children offers further support to suggest that 1.6° is an appropriate figure.