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Assessing the Strength of the Evidence

Approach for the Literature Review

WYSAC researchers began the 2012 literature review by searching for environmental prevention strategies indexed in the Cochrane database, the National Registry of Evidence-based Programs and Practices (NREPP) registry, and The Community Guide to Preventive Services.

If a systematic review could be located in any one of these sources, researchers moved on to review the next strategy.

If no evidence could be located, they continued by searching The MayaTech Corporation’s Environmental Strategies Selection Guide for relevant articles (Pettibone, Kowalczyk, & Laestadius, 2006). Again, if no evidence could be located, they searched three databases: PubMed/Medline, CINAHL (EBSCOhost), and PsycInfo (EBSCOhost).

If researchers still did not have sufficient evidence, they searched Google Scholar and retrieved the most up-to-date, and highly-cited articles. Finally, in the event that no articles or literature could be located, they performed a Google search for grey literature.

In an effort to locate the most prominent and recent publications, researchers restricted their search to articles published after 1999. However, if no articles were located, they expanded the search to include earlier literature. This review process was not designed to be an exhaustive search of the literature. Instead, the goal was to find the most prominent, current articles related to each strategy.

2017/18 Update

When WYSAC researchers updated this tool they again consulted the Cochrane Drug and Alcohol Reviews, Community Guide to Prevention, University of Minnesota Alcohol Epidemiology Program, University of Wisconsin Population Health Institute, and County Health Rankings and Roadmaps.

If there were new systematic reviews, updates of previous reviews, or changes in recommendations for a strategy in these sources, the  Discussion of Effectiveness section from the previous version of this catalog was revised and the References section.

When a strategy description referenced a Wyoming statute, researchers updated and revised statute references in the “Description of Strategy” section when necessary. Other than updating findings from these four sources and the Wyoming statutes, no other changes were made to the 2012 strategies.

In response to changes in prevention needs, WYSAC researchers added two environmental strategy literature reviews targeting opioid prevention in 2018. The two added environmental strategies were Naloxone Education and Distribution Programs and Prescription Drug Monitoring Programs (PDMPs).

Researchers first sourced the Cochrane Drug and Alcohol Reviews, Community Guide to Prevention, and University of Wisconsin Population Health Institute, County Health Rankings and Roadmaps for systematic reviews of naloxone education and distribution program and PDMPs. Researchers also cited a single, large-scale, recent study for each of these topics.

Evidence Sources

No Evidence Found


This evidence category indicates that there is inadequate research to evaluate the effectiveness of the strategy. A strategy with no evidence may be relatively new and not yet evaluated, or the peer-reviewed articles on the strategy may lack quantitative analysis of outcomes.

Grey Literature


Grey literature refers to written material that is produced by an institute and/or organization that has not been published in peer-reviewed, academic journals.

Single Published Study

This evidence category refers to a single published study that has appeared in a peer-reviewed, academic journal.

Numerous Published Studies

This evidence category refers to strategies with evidence from multiple studies that have appeared in peer-reviewed, academic journals.

Systematic Review

A systematic review is a critical assessment and evaluation of all research studies that address a particular issue (US Department of Health and Human Services, n.d.). In most cases, researchers use an organized method of locating, assembling, and evaluating a given body of literature on a particular topic using a set of specific criteria (US Department of Health and Human Services, n.d.).


Meta-analysis refers to a method of combining data from multiple research studies that is similar to a systematic review, but which includes a statistical process that combines findings from individual studies (US Department of Health and Human Services, n.d.).

Cochrane Review


Cochrane Reviews are systematic reviews published by the Cochrane Collaboration—an international network of healthcare professionals that prepares, maintains, and promotes the accessibility of systematic reviews on a range of health topics. Cochrane Reviews cover primary research in human health care and health policy and are internationally recognized as the highest standard in evidence-based health care (The Cochrane Collaboration, 2012).

Community Guide

The Guide to Community Preventive Services (The Community Guide) is a resource for information on evidence-based prevention strategies, recommendations, and findings about what works to improve public health. The Community Guide represents a credible resource based on a scientific systematic review process that provides answers to questions that are critical to public health (The Guide to Community Preventive Services, 2012).


The National Registry of Evidence-Based Programs and Practices (NREPP) is a service of the Substance Abuse and Mental Health Services Administration (SAMHSA) that provides a searchable online registry of mental health and substance abuse interventions that have been reviewed and rated by independent reviewers. The purpose of NREPP is to assist the public in identifying scientifically-based approaches to preventing and treating mental and/or substance use disorders that can be readily disseminated to the field (National Registry of Evidence-Based Programs and Practices, 2012).