In this special 2-part blog post, our authors will take us on a detailed guide of conducting systematic reviews and meta-analyses.
To any of you readers who are looking at conducting such reviews for the first time, and indeed those who wish to brush up and revise the processes involved; this is a gold mine. Every section is crammed full of informative details, handy tips, and invaluable links to useful resources. This post will cover the steps involved in in planning review studies, that is; scoping, developing review questions, informing the eligibility criteria, and submitting a protocol.
Hold on to your desk blog readers, because things are about to get systematically meta.
An introductory review of review basics
Types of review
There are different kinds of reviews such as literature reviews, narrative reviews, rapid reviews, scoping reviews, and systematic reviews.
A systematic review is a literature review designed to locate, appraise, and synthesise the best available evidence relating to a specific research question in order to provide informative and evidence-based answers.
Systematic review steps
We divided the steps for a systematic review into 7 steps: Planning your review (e.g., writing your protocol), running the search, screening and selecting studies, data extraction, quality assessment, analysis and synthesis (e.g., meta-analysis), and writing up your report.
Step 1 : Planning (i.e., Prior Planning Prevents Poor reviews).
Scoping, Developing Review Question(s), Search Strategy, Protocol.
Having a clear and comprehensive plan is the first step for conducting a systematic review. You should develop an action plan for your review and detail all the steps you will follow before conducting the search. There are different ways and different guidance for conducting a good systematic review. Do not forget, being flexible is good if you have a good reason to be!
Before developing your review question(s), it is good to check what is available in the field. How many studies are there? What are their research designs? What outcomes they used? Are there any recently completed or ongoing reviews on the same subject? This is to have a feel about the literature and to see if it is feasible to conduct this review, and to shape your final research questions. Also, you do not want to end up seeing a publication that reviewed the same subject as you after months of work, right? In this step simply search your key words on google scholar, library etc., to see published studies. To check the completed/ongoing reviews, you can additionally check PROSPERO and Cochrane Database of Systematic Reviews (CDSR). Our aim in here is to make sure we have sufficient number of studies to conduct a systematic review, and to avoid conducting the same review with recently completed or ongoing review.
Developing review question(s).
Next, you need to develop clear and well-defined review questions. This should reflect what your review intends to answer. There are some tools that helps us to formulate review questions such as PICOS, SPIDER, COSMIN. Each has different approaches and focuses to develop a well-built question. For example, PICO is mostly used for systematic review of clinical trials. It includes five main concepts: Population, intervention, comparison, outcome, and study design. You can review these tools and use/ adapt them based on your review’s focus and finalise your review question.
Eligibility criteria are related to our review questions. However, we may need to further clarify on what we will include and exclude from our review. For example, let’s say your review question is “what is the efficacy of acceptance and commitment therapy compared to cognitive therapy for improving well-being in adults with chronic pain?”. Here we understand the focus is on adults, but what is the age range we are interested in? Are we going to consider 16 as adults in our review or not? There are different acceptance and commitment therapy-based interventions, which do we intend to include? All? Are we going to focus on RCTs? Are we going to exclude case studies or grey literature? What will be considered as well-being (e.g., quality of life, life satisfaction, positive affect)? What about the studies published in non-English language? These are all important issues, and we need to clarify all the planned inclusion and exclusion criteria before developing the search strategy and conducting the search.
Search strategy is probably the most critical step in conducting a systematic review.
It is based on both research question and eligibility criteria. This strategy will determine what you will include or not include in your review. Therefore, it must be well-developed. The academic librarian of the university offers advice on developing search strategy for systematic reviews. It is always better to ask an expert opinion in this step, therefore consulting a librarian would be beneficial. With the librarian, you can discuss the search terms and the databases you plan to use and receive further recommendations. You should review the developed search terms and search strategy carefully. For search terms, we need to consider any synonyms, related terms, or different spellings (e.g., English and American). We also need to identify the databases we will conduct the search on. Some of the databases we frequently use in psychology are EMBASE, MEDLINE, and PsycINFO. Additionally, if you plan to include dissertations/theses, you should consider ProQuest Dissertations & Theses Global database. You should consider your topic and review questions and decide on the databases.
Submitting a Protocol.
It is highly recommended to have a submitted protocol for your review. If you conduct a Cochrane review, you must have a protocol. This will increase the transparency of your review process and it will also protect you from any possible duplication problems. While different websites/databases can be used to for submitting a protocol, PROSPERO can be used to register your protocol if you have a health-related (e.g., nursing, clinical psychology) review. This is one of the most used international databases of prospectively registered systematic reviews. It usually requires author to identify a title, key words, review question(s), objectives, and the methods for conducting a systematic review. This protocol should ideally be submitted before conducting the search.
End of part 1. Stay tuned for the next exciting episode.
If you want to find out more resources for conducting your systematic review and meta-analysis, please click here or drop us an email!