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ENVS 7997: Integrated Environmental Issues: Introducing Systematic Reviews

How Can We Help?

Librarians at Louisiana State University can help you: 

  • Identify relevant databases in which to conduct literature searches related to your topic.
  • Design and implement complex, comprehensive search strategies to maximize retrieval of relevant studies.
  • Use reference management software, such as Endnote and other tools to manage the study gathering and selection process.
  • Create search alerts to ensure that new studies are found while the systematic review is in progress.
  • Find existing systematic reviews and protocols to inform your own protocol development.
  • Track down hard-to-find full-text articles for screening and review.

Finding Existing Systematic Reviews

What is a Systematic Review?

A systematic review is a methodical and comprehensive literature synthesis focused on a well-formulated research question.  Its aim is to identify and synthesize all of the scholarly research on a particular topic, including both published and unpublished studies. Systematic reviews are conducted in an unbiased, reproducible way to provide evidence for practice and policy-making and identify gaps in research.  They may involve a meta-analysis

Systematic reviews are much more time-intensive than traditional literature reviews.  They usually require a multi-person research team. Before embarking on a systematic review, it is important to determine whether the body of literature warrants one and to clearly identify your reasons for conducting a systematic review. 

Narrative reviews articles may be evidence-based, but they are NOT evidence (research). They usually lack systematic search protocols or explicit criteria for selecting and appraising evidence. Instead, they rely on experts to gather evidence and synthesize findings. 

Systematic Reviews need to have more than one author in order to be considered "systematic". A team can help cut down on bias, make judgment calls on allowing articles, and many journals will reject a study if it is labeled systematic review but only has one author. 

Systematized Review is what most people in graduate schools are actually looking to do.

"Systematized reviews attempt to include one or more elements of the systematic review process while stopping short of claiming that the resultant output is a systematic review. They may identify themselves parenthetically as a systematic’ review. Systematized reviews are 
typically conducted as a postgraduate student assignment, in recognition that they are not able to draw upon the resources required for a full systematic review (such as two reviewers).

Perceived strengths. Typically, the search stage possesses the most easily identified elements of systematicity and an author may conduct a comprehensive search but do little more than simply catalogue included studies. Conversely, the author might only search one or more databases and then code and analyse all retrieved results in a
systematic manner. The resulting output ‘models’ the systematic review process and allows the author to demonstrate an awareness of the entire process and technical proficiency in the component steps, However, such a review necessarily falls short of being able to claim the comprehensiveness so fundamental to the systematic review method. Such reviews may form the basis for a more extensive piece of work either as a dissertation or a fully funded research project.

Perceived weaknesses.
For such reviews quality assessment and synthesis may be less identifiable. This means that these processes are not described, that they are modelled using a small set of eligible articles or that they are missing entirely. While the attempt at systematicity is to be welcomed, such reviews do possess a greater likelihood of bias than those that adhere more strictly to guidelines on the conduct of systematic reviews (see above). Completion of the academic requirements for the review is prioritized over methodological considerations."

Grant, MJ & Booth, A 2009, 'A typology of reviews: an analysis of 14 review types and associated methodologies', Health Information & Libraries Journal, vol. 26, no. 2, pp. 91-108.

Systematic Review v. Traditional Literature Review

Systematic Review Well-defined research question to be answered by the review.  Conducted with the aim of finding all existing            evidence in an unbiased, transparent, and    reproducible way.  Attempts are made to find ALL existing       published and unpublished literature on the      research question. The process is documented and reported. Reasons for including or excluding studies are explicit and informed by the research         question. Systematically assess risk of bias of individual studies and overall quality of the evidence,   including sources of heterogeneity between study results.  Base conclusion on quality of the studies an provide recommendations for practice or to address knowledge gaps.  Traditional Literature Review Topics may be broad in scope, the goal of the review may be to place one’s own research within the existing body of knowledge, or to gather information that supports a particular viewpoint. Searches maybe ad hoc, and based on what the author is already familiar with. Searches are not as exhaustive or fully comprehensive. Often lack clear reasons why studies were     included or excluded from the review.  Often do not consider study quality of          potential biases in study design.  Conclusions are more qualitative and may not be based on study quality.

What is a Meta-Analysis?

Meta-Analysis: a quantitative statistical analysis of several separate but similar experiments or studies in order to test the pooled data for statistical significance [often found within systematic reviews, but not the same]. – Definition from www.merriam-Webster.com   

All meta-analyses should be part of a systematic review, but not all systematic reviews will include a meta-analysis.

Systematic reviews are usually researched and written as a group to remove any questions, biases, or doubts about a specific item.  A systematic review really should NOT be attempted by 1 person alone, there could be too many validity/reliability questions raised by reviewers.

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