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Table 1 Quality criteria for measurement properties

From: Measurement properties of asthma-specific quality-of-life measures: protocol for a systematic review

Property Rating Quality criteria
Reliability   
  Internal consistency + (Sub)scale unidimensional AND Cronbach's alpha(s) ≥0.70
? Dimensionality not known OR Cronbach's alpha not determined
- (Sub)scale not unidimensional OR Cronbach's alpha(s) <0.70
  Measurement error + MIC > SDC OR MIC outside the LOA
? MIC not defined
- MIC ≤ SDC OR MIC equals or inside LOA
  Reliability + ICC/weighted kappa ≥0.70 OR Pearson's r ≥ 0.80
? Neither ICC/weighted kappa, nor Pearson's r determined
- ICC/weighted kappa <0.70 OR Pearson's r < 0.80
Validity   
  Content validity + All items are considered to be relevant for the construct to be measured, for the target population and for the purpose of the measurement AND the questionnaire is considered to be comprehensive
? Not enough information available
- Not all items are considered to be relevant for the construct to be measured, for the target population and for the purpose of the measurement OR the questionnaire is considered not to be comprehensive
Construct validity   
  Structural validity + Factors should explain at least 50% of the variance
? Explained variance not mentioned
- Factors explain <50% of the variance
  Hypothesis testing + Correlation with an instrument measuring the same construct ≥0.50 OR at least 75% of the results are in accordance with the hypotheses AND correlation with related constructs is higher than with unrelated constructs
? Solely correlations determined with unrelated constructs
- Correlation with an instrument measuring the same construct <0.50 OR <75% of the results are in accordance with the hypotheses OR correlations with related constructs are lower than with unrelated constructs
Responsiveness   
  Responsiveness + Correlation with changes on instruments measuring the same construct ≥0.50 OR at least 75% of the results are in accordance with the hypotheses OR AUC ≥0.70 AND correlation with changes in related constructs are higher than with unrelated constructs
? Solely correlations determined with unrelated constructs
- Correlations with changes on instruments measuring the same construct <0.50 OR <75% of the results are in accordance with the hypotheses OR AUC <0.70 OR correlations with changes in related constructs are lower than with unrelated constructs
  1. Plus sign indicates positive rating; question mark, indeterminate rating and minus sign, negative rating. MIC minimal important change, SDC smallest detectable change, LOA limits of agreement, ICC intraclass correlation coefficient, AUC area under the curve.