Systematic Reviews and systematically searching the literature are two different research methods. There are 14 different types of reviews you could undertake so please understand the difference.
Systematic Reviews require data synthesis for the meta-analysis and often take months to complete.
Reproduced from: Bettany-Saltikov, J. (2010). Learning how to undertake a systematic review: Part 1. Nursing Standard, 24(40): 47-55.
|Systematic Review||Literature Review|
|Question||Focused on a single question||Not necessarily focused on a single question, but may describe an overview|
|Protocol||A peer review protocol or plan is included||No protocol is included|
|Background||Both provide summaries of the available literature on a topic|
|Objectives||Clear objectives are identified||Objectives may or may not be identified|
|Inclusion and Exclusion Criteria||Criteria stated before the review is conducted||Criteria not specified|
|Search Strategy||Comprehensive search conducted in a systematic way||Strategy not explicitly stated|
|Process of Selecting Articles||Usually clear and explicit||Not described in a literature review|
|Process of Evaluating Articles||Comprehensive evaluation of study quality||Evaluation of study quality may or may not be included|
|Process of Extracting Relevant Information||Usually clear and specific||Not clear or explicit|
|Results and Data Synthesis||Clear summaries of studies based on high quality evidence||Summary based on studies where the quality of the articles may not be specified. May also be influenced by the reviewer's theories, needs and beliefs|
|Discussion||Written by an expert or group of experts with a detailed and well grounded knowledge of the issues|
A meta-analysis goes beyond critique and integration and conducts secondary statistical analyses on the outcomes of similar studies. It is a systematic review that uses quantitative methods to synthesize and summarize the results.
An advantage of a meta-analysis is the ability to be completely objective in evaluating research findings. Not all topics, however, have sufficient research evidence to allow a meta-analysis to be conducted. In that case, an integrative review is an appropriate strategy.
A meta-analysis may be part of a systematic review.
What is a meta-synthesis?
First of all, what is a meta-synthesis? According to Screiber et al. (1997, p.314), a meta-synthesis “is bringing together and breaking down of findings, examining them, discovering essential features and, in some way , combining phenomena into a transformed whole” In basic terms, a meta-synthesis is the ‘bringing together’ of Qualitative data to form a new interpretation of the research field.
Meta-synthesis Vs. Meta-analysis: Whats the difference?
Unlike a meta-analysis which is used to aggregate findings to establish ‘truths’, for example, if an intervention has a true effect on a variable, a meta-synthesis can lead to new interpretations of research. This can result in new theories being developed.
In summary, a meta-analysis is a way of testing a hypothesis whereas a meta-synthesis is a way of developing a new theory.
Three main types of Meta-synthesis
1) Theory Building – This form of meta-synthesis brings together findings on a theoretical level to build a tentative theory.
2) Theory Explication – This form of meta-synthesis is a way of reconceptualising the original phenomenon.
3) Descriptive – This form of meta-synthesis provides a broad description of the research phenomenon.
These forms of meta-synthesis are not discrete, they are complimentary. The aim of Meta-synthesis usually overlap as you will see in the example later on.
Why use a meta-synthesis?
Qualitative data is useful for providing a snapshot at one person’s interpretation of an event or phenomenon. By bringing together many different interpretations you are strengthening the evidence for an interpretation by discovering common themes and differences & building new interpretations of the topic of interest.
A literature review is something most of you have done this at one time or another. As a publication type it is an article or book published after examination of previously published material on a subject. It may be comprehensive to various degrees and the time range of material scrutinized may be broad or narrow, but the reviews most often desired are reviews of the current literature. The textual material examined may be equally broad and can encompass, in medicine specifically, clinical material as well as experimental research or case reports. State-of-the-art reviews tend to address more current matters. A review of the literature must be differentiated from HISTORICAL ARTICLE on the same subject, but a review of historical literature is also within the scope of this publication type. The literature review examines published materials which provide an examination of recent or current literature. Review articles can cover a wide range of subject matter at various levels of completeness and comprehensiveness based on analyses of literature that may include research findings. The review may reflect the state of the art. It also includes reviews as a literary form.
An integrative review summarizes past research and draws overall conclusions from the body of literature on a particular topic. The body of literature comprises all studies that address related or identical hypotheses. In a properly executed integrative review, the effects of subjectivity are minimized through carefully applied criteria for evaluation. A well-done integrative review meets the same standards as primary research in regard to clarity, rigor and replication.
At its most basic, narrative reviews are most useful for obtaining a broad perspective on a topic and are often more comparable to a textbook chapter including sections on the physiology and/or epidemiology of a topic.
When reading and evaluating a narrative review, keep in mind that author's bias may or may not be present. The labels Narrative Review and Literature Review are often describing the same type of review.
For scientific purposes, the term Literature Review is the one used most often.
A literature review is an essay that surveys, summarizes, links together, and assesses research in a given field. It surveys the literature by reviewing a large body of work on a subject; it summarizes by noting the main conclusions and findings of the research; it links together works in the literature by showing how the information fits into the overall academic discussion and how the information relates to one another; it assesses the literature by noting areas of weakness, expansion, and contention. This handout reviews the essentials of literature review construction by discussing the major sectional elements, their purpose, how they are constructed, and how they all fit together.
All literature reviews have major sections:
In Literature Reviews, it is Not Appropriate to:
Remember, a literature review is not a book report. A literature review is focus, sisinct, organized, and is free of personal beliefs or unsubstantiated tidbits.
1. Choose a topic. Define your research question.
Your literature review should be guided by a central research question. Remember, it is not a collection of loosely related studies in a field but instead represents background and research developments related to a specific research question, interpreted and analyzed by you in a synthesized way.
1) Make sure your research question is not too broad or too narrow. Is it manageable?
2) Begin writing down terms that are related to your question. These will be useful for searches later.
3) If you have the opportunity, discuss your topic with your professor.
2. Decide on the scope of your review.
How many studies do you need to look at? How comprehensive should it be? How many years should it cover?
1) This may depend on your assignment.
2) How many sources does the assignment require?
3. Select the databases you will use to conduct your searches.
Make a list of the databases you will search. Remember to include comprehensive databases such as WorldCat and Dissertations & Theses, if you need to.
1) Look at the Library's research guides in your discipline to select discipline-specific databases. Don't forget to look at books
2) Make an appointment with or contact your subject librarian to make sure you aren't missing major databases.
4. Conduct your searches and find the literature. Keep track of your searches!
1) Review the abstracts of research studies carefully. This will save you time.
2) Write down the searches you conduct in each database so that you may duplicate them if you need to later (or avoid dead-end searches that you'd forgotten you'd already tried).
3) Use the bibliographies and references of research studies you find to locate others.
4) Ask your professor or a scholar in the field if you are missing any key works in the field.
5) Use a citation manager (Zotero or Endnote Web) to keep track of your research citations.
5. Review the literature. Some questions to help you analyze the research:
1) What was the research question of the study you are reviewing? What were the authors trying to discover?
2) Was the research funded by a source that could influence the findings?
3) What were the research methodologies? Analyze its literature review, the samples and variables used, the results, and the conclusions. Does the research seem to be complete? Could it have been conducted more soundly? What further questions does it raise?
4) If there are conflicting studies, why do you think that is?
5) How are the authors viewed in the field? Has this study been cited?; if so, how has it been analyzed?
6) Again, review the abstracts carefully.
7) Keep careful notes of your searches so others may track your thought processes during the research process.