Appendix 3: AMSTAR tool (Shea et al., 2007)

AMSTAR – A Measurement tool to assess the methodological quality of systematic reviews (of RCTs)


1. Was an ‘a priori’ design provided? ___Yes ____No ____ Can’t Answer ____ N/A

The research question and inclusion criteria should be established before the conduct of the review.

Note: Need to refer to a protocol, ethics approval, or pre-determined/ a priori published research objective to score a ‘yes’.

2. Was there duplicate study selection and data extraction? ___Yes ____No ___ Can’t Answer ___ N/A

There should be at least two independent data extractors and a consensus procedure for disagreements in place.

Note: 2 people do study selection, 2 people do data extraction, consensus process or one person checks the other’s work.

3. Was a comprehensive literature search performed? ___Yes ____No ___ Can’t Answer ___ N/A

At least two electronic sources should be searched. The report must include years and databases used (e.g., Central, EMBASE, MEDLINE). Key words and/or MESH terms must be stated and, where feasible, the search strategy should be provided. All searches should be supplemented by consulting current contents, reviews, textbooks, specialized registers, or experts in the particular field of study, and by revewing the references in the studies found.

Note: If at least 2 sources + one supplementary strategy used, select ‘yes’ (Cochrane register/Central counts as 2 sources; a grey literature search counts as supplementary).

4. Was the status of publication (i.e., grey literature) used as an inclusion criterion? ___Yes ____No ___ Can’t Answer ___ N/A

The authors should state that they searched for reports regardless of their publication type. The authors should state whether or not ehy excluded any reports (from the systematic review), based on their publication status, language, etc.

Note: If review indicates that there was a search for ‘grey literature’ or ‘unpublished literature’ indicate ‘yes’. SIGLE database, dissertations, conference proceeedings, and trial registries are all considered grey for this purpose. If searching a source that contains both grey and non-grey, it must specify that they were searching for grey/unpublished literature.

5. Was a list of studies (included and excluded) provided? ___Yes ____No ___ Can’t Answer ___ N/A

A list of included and excluded studies should be provided.

Note: Acceptable if the excluded studies are referenced. If there is an electronic link to the list but the link is dead, select ‘no’.

6. Were the characteristics of the included studies provided? ___Yes ____No ___ Can’t Answer ___ N/A

In an aggregated form, such as a table, data from the original studies should be provided on the participants, interventions and outcomes. The ranges of characteristics in all the studies analyzed e.g., age, race, sex, relevant socioeconomic data, disease status, duration, severity, or other diseases should be reported.

Note: Acceptable if not in table format as long as they are described as above.

7. Was the scientific quality of the included studies assessed and documented? ___Yes ____No ___ Can’t Answer ___ N/A

‘A priori’ methods of assessment should be provided (e.g., for effectiveness studies if the authors chose to include only randomized, double-blind, placebo controlled studies, or allocation concealment as inclusion criteria); for other types of studies alternative items will be relevant.

Note: Can include use of a quality scoring tool or checklist, e.g., Jada scale, risk of bias, sensitivity analysis, etc., or a description of quality items, with some kind of result for EACH study (‘low’ or ‘high’ is fine, as long as it is clear which studies score ‘low’ and ‘high’; a summary score/range for all studies is not acceptable).

8. Was the scientific quality of the included studies used appropriately in formulating conclusions? ___Yes ____No ___ Can’t Answer ___ N/A

The results of the methodological rigor and scientific quality should be considered in the analysis and the conclusions of the review, and explicitly stated in formulating recommendations.

Note: Might say something such as ‘the results should be interpreted with caution due to poor quality of included studies.’ Cannot score ‘yes’ for this question if scored ‘no’ for question 7.

9. Were the methods used to combine the findings of studies appropriate? ___Yes ____No ___ Can’t Answer ___ N/A

For the pooled results, a test should be done to ensure the studies were combinable, to assess their homogeneity (i.e., Chi-squared test for homogeneity). If heterogeneity exists, a random effects model should be used and/or the clinical appropriateness of combining should be taken into consideration (i.e., is it sensible to combine?).

Note: Indicate ‘yes’ if they mention or describe heterogeneity, i.e., if they explain that they cannot pool because of heterogeneity/variability between interventions.

10. Was the likelihood of publication bias assessed? ___Yes ____No ___ Can’t Answer ___ N/A

An assessment of publication bias should include a combination of graphical aids (e.g., funnel plot, other available tests) and/or statistical tests (e.g., Egger regression test, Hedges-Olken).

Note: If no test values or funnel plot included, sore ‘no’. Score ‘yes’ if it mentions that publication bias could not beassessed because there were fewer than 10 included studies.

11. Was the conflict of interest included? ___Yes ____No ___ Can’t Answer ___ N/A

Potential sources of support should be clearly acknowledged in both the systematic review and the included studies.

Note: To get a ‘yes,’ it must indicate the source of funding or support for the systematic review AND for each of the included studies.


Shea et al. BMC Medical Research Methodology 2007, 7:10

Additional notes (in italics) made by Michelle Weir, Julia Worswick, and Carolyn Wayne based on conversations with Bev Shea and/or Jeremy Grimshaw in June and October 2008 and July and September 2010.