Risk of bias in model-based economic evaluations: the ECOBIAS checklist

Abstract

Several biases can occur when performing economic evaluations (EE) and it is important for researchers to minimize these biases, as they can significantly affect economic outcomes. This review aims, firstly, to identify biases that can occur in model-based EE and to illustrate their impact on economic outcomes and, secondly, to present a checklist for assessing the overall risk of bias in EE. Eleven biases that can occur in model-based studies were identified through a scoping review, scrutiny of systematic reviews, the authors’ own experiences and discussions with experts. By combining these biases that can occur in model-based studies with biases that were identified for trial-based studies in a previous article, a 22-item checklist was developed for assessing bias in EE – the ECOBIAS checklist. This study and the ECOBIAS checklist aim to help researchers reduce biases in future EE, particularly in model-based EE. Nevertheless, further validation of the checklist is needed.

KEYWORDS:

• bias
• model-based studies
• cost and outcomes
• economic evaluation
• systematic error
• checklist

Acknowledgement

The authors thank the discussants of the lowlands Health Economics Study Group (lolaHESG) 2015, in particular Janneke Grutters, the discussants of the 2nd EuHEA PhD student-supervisor conference, in particular Graham Scotland, and our external experts Matthijs van den Berg and Bram Ramaekers, for their input on their input regarding the illustrations of the biases’ and for their valuable feedback on an earlier draft of the article.

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.