Consistencia interna y validez de contenido del instrumento DELBI

Objectives: To assess internal consistency and content validity of the DELBI scale used to
evaluate clinical practice guidelines (CPG).
Methods: The DELBI scale was applied to a selection of 146 CPG for breast, colorectal and
prostate cancer. Internal consistency of the full scale and by domains was assessed using
Cronbach‘s alpha coefficient, and the content validity was assessed using an Exploratory Factor Analysis (EFA) with orthogonal rotation and a Confirmatory Factor Analysis (CFA) applying structural equation modelling. Bartlett’s test of sphericity and KMO test were used to determine the factorability of the intercorrelation matrix, with the ordinal nature of the item-scores
as a Likert-type scale. Estimation methods were performed using polychoric correlation, and
asymptotic covariance matrices.
Results: For the full scale, a good internal consistency was observed (0.89), which varies between 0.46 and 0.74 by domains. A four-factor structure was found: applicability, clarity and presentation, rigour of development, and stakeholder involvement. The goodness-of-fit tests of the scale organised by 4 domains was better than the 8 domains from the original scale and had a better internal consistency.
Conclusions: It is concluded that the scale has acceptable psychometric properties and it is
suggested to consider four dimensions of quality of CPGs in the interpretation of the evaluations
performed with the DELBI scale.