Table 1 Advantages and limitations of distribution-based, anchor-based, and instrument-defined methods for MCID calculation
Method | Advantages | Limitations |
|---|---|---|
Considering measurement precision Clear formula, easy to implement | Based on statistical distributions of data and the reliability of the instrument, so that the MCID would be affected by the sample and the measurement characteristics of instrument itself Several different values may be obtained based on different calculation formulas Not based on changes in patient-reported results and therefore does not provide a good indication of the importance of the observed changes | |
Define “minimal importance” explicitly and incorporate it into these methods Can provide MCID with clinically significant explanations | Anchor question may not fully capture changes in the PROs that may reflect more than one type of outcome MCID depends on what transition rating on the anchor question is considered as “clinically important” Does not consider measurement precision Recall bias | |
Instrument-defined [34] | A simple method that can be easily applied by other researchers to calculate the MCIDs for the studied instruments using scoring algorithms for other populations Using several health transitions as reference points or standards for minimally important change, resulting in MCID based on multiple internal anchors Does not require collection of primary data; thus, it is resource- and time- saving | Some instrument-defined health transitions may not occur in reality, which may lead to biased estimates Some health transitions used may represent trivial or large changes that may lead to biased estimates Some “smallest” health transitions may represent changes that are larger than the MCID |