A multicentre validation study of the Swedish version of the Normalization Process Theory Measure S-NoMAD

The Normalization Process Theory (NPT) is increasingly used for evaluating and understanding implementation processes of complex care interventions. One key tool for applying the NPT in research and practice is the NoMAD questionnaire, which offers a structured approach to examination of the four constructs that according to the NPT are central in implementation and normalisation processes. We aimed to evaluate the psychometric properties of the Swedish version S-NoMAD.

Secondary analysis was performed on pooled S-NoMAD survey data from six implementation studies in different health and social care contexts. The NPT factor structure was tested by confirmatory factor analysis (CFA). Internal construct reliability was tested using Cronbach's alpha. Validity was confirmed by assessing the fit of the CFA using the fit measures Comparative Fit Index, Tucker-Lewis Index, root mean square error of approximation and standardised root mean square residual. Pearson correlations amongst the latent construct and general questions about the intervention were calculated.

The estimation results of the CFA indicate that the four-factor model implied by the NPT fits the data reasonably well. The factor loadings are of good sizes and the fit indices do not imply a mis-specified model. A good internal construct validity, indicated by a good model fit to the NPT four-construct model and acceptable to good internal reliability, was shown. External validity was also demonstrated.

The CFA results indicate that the S-NoMAD has good psychometric properties for capturing perceptions of people involved in various Swedish implementation studies conducted in both health and social care contexts, demonstrating its general applicability. They show that the S-NoMAD, unlike the majority of instruments for evaluation of implementation processes, is not context- and intervention-specific. The findings highlight the utility of the S-NoMAD and show that it meets some important criteria for pragmatic measures. Further studies are warranted on different interventions implemented in diverse contexts regarding the meaning of the magnitude of the NoMAD scores in order to clarify its potential value as a tool for assessment of implementation strategies and on psychometric properties beyond construct validity and internal construct reliability, for example on test-retest reliability and longitudinal studies focusing on responsiveness.