Article type
Abstract
Background:
The vast number of primary studies published demonstrates the need for evidence syntheses. Over the past decades, methodologies of evidence syntheses have evolved considerably, reflecting their origin in various research traditions and disciplines with differing practice needs, and today there are numerous types. While they share many similarities in their approaches it is important to distinguish between different review types with correct terminology and typology, and understand their central characteristics, methods, and applications. However, terms and methods guides are used inconsistently in the literature, posing challenges.
Objectives:
To identify and describe the methodological literature for the most common types of evidence syntheses (reviews).
Methods:
We conducted a scoping review. Based on pre-set inclusion criteria, a search specialist conducted a systematic literature search in MEDLINE, and searched in OpenAlex, Google scholar, organisations’ websites. Records (titles/abstract, full texts) were screened by two independent reviewers. We classified the publications based on type of review, extracted data on purpose and methodological characteristics (e.g. protocol, search, risk of bias assessment, synthesis), and conducted descriptive analyses.
Results:
The search resulted in 850 records of which we screened 108 in full text. We included 96 publications describing one or more of our 14 chosen review types. There was great variety in the number of and detail of methodological guides for each type, ranging from one guide to ten. There was similar variety in requirements, including: writing a protocol (9), conducting a systematic and extensive literature search (10), reporting of search (11), assessing risk of bias (5). For example, for critical review we only found one guide, with approach described in vague terms, whereas for scoping reviews there were detailed descriptions of each step of the review from several methods guides. Seven of the 14 types have a reporting standard.
Conclusions:
There is great variety in reviews’ purposes and extent of published methodological guidance for their conduct. The scoping review details which methodological guides to use for which review.
The vast number of primary studies published demonstrates the need for evidence syntheses. Over the past decades, methodologies of evidence syntheses have evolved considerably, reflecting their origin in various research traditions and disciplines with differing practice needs, and today there are numerous types. While they share many similarities in their approaches it is important to distinguish between different review types with correct terminology and typology, and understand their central characteristics, methods, and applications. However, terms and methods guides are used inconsistently in the literature, posing challenges.
Objectives:
To identify and describe the methodological literature for the most common types of evidence syntheses (reviews).
Methods:
We conducted a scoping review. Based on pre-set inclusion criteria, a search specialist conducted a systematic literature search in MEDLINE, and searched in OpenAlex, Google scholar, organisations’ websites. Records (titles/abstract, full texts) were screened by two independent reviewers. We classified the publications based on type of review, extracted data on purpose and methodological characteristics (e.g. protocol, search, risk of bias assessment, synthesis), and conducted descriptive analyses.
Results:
The search resulted in 850 records of which we screened 108 in full text. We included 96 publications describing one or more of our 14 chosen review types. There was great variety in the number of and detail of methodological guides for each type, ranging from one guide to ten. There was similar variety in requirements, including: writing a protocol (9), conducting a systematic and extensive literature search (10), reporting of search (11), assessing risk of bias (5). For example, for critical review we only found one guide, with approach described in vague terms, whereas for scoping reviews there were detailed descriptions of each step of the review from several methods guides. Seven of the 14 types have a reporting standard.
Conclusions:
There is great variety in reviews’ purposes and extent of published methodological guidance for their conduct. The scoping review details which methodological guides to use for which review.