OBJECTIVES: In evidence-based medicine, systematic literature review (SLR) methods have been developed to answer a single, carefully formulated research question, whereas health economic models have multiple, and often, evolving information needs. There is very little guidance on how to search for evidence to inform HE model inputs. The aim of this literature review is to determine which information retrieval techniques are recommended in HTA agency and HE modelling guidelines, and whether these vary by model input parameter type.

METHODS: A web search was conducted in May 2023. Publications were included in this review if they were HTA submission or HE guideline, and if HE model input identification recommendations were included in the document. A data extraction grid was developed by input parameter type.

RESULTS: In total, 59 publications were identified from 48 agencies representing 45 countries. Multinational guidelines were also identified. Identification of treatment effect was associated with the most detailed search method recommendations. Search recommendations were also given for adverse events and health state utility values in some of the guidelines. All methods were referring to systematic literature review method publications. Methodological advice was rarely given regarding the identification of evidence on costs, resource use and baseline event risks.

CONCLUSIONS: Overall, a limited number of search method publications are referenced in the HTA and HE modelling guidelines. These tend to focus on comprehensive identification of treatment effects in the manner of full systematic literature reviews. Model developers would benefit from methodological guidance based on empirical research that considers the search methods for each of the input parameter types.