STEP 1: FRAMING THE QUESTION – The research question may initially be stated as a query in free form but reviewers prefer to pose it in a structured and explicit way. The relations between various components of the question and the structure of the research design are shown in Figure 1, This paper focuses only on the question of safety related to the outcomes described below. Structured questions for systematic reviews and relations between question components in a comparative study Box 1 The steps in a systematic review
Step 1: Framing questions for a review The problems to be addressed by the review should be specified in the form of clear, unambiguous and structured questions before beginning the review work. Once the review questions have been set, modifications to the protocol should be allowed only if alternative ways of defining the populations, interventions, outcomes or study designs become apparent Step 2: Identifying relevant work The search for studies should be extensive. Multiple resources (both computerized and printed) should be searched without language restrictions. The study selection criteria should flow directly from the review questions and be specified a priori, Reasons for inclusion and exclusion should be recorded Step 3: Assessing the quality of studies Study quality assessment is relevant to every step of a review. Question formulation (Step 1) and study selection criteria (Step 2) should describe the minimum acceptable level of design. Selected studies should be subjected to a more refined quality assessment by use of general critical appraisal guides and design-based quality checklists (Step 3). These detailed quality assessments will be used for exploring heterogeneity and informing decisions regarding suitability of meta-analysis (Step 4). In addition they help in assessing the strength of inferences and making recommendations for future research (Step 5) Step 4: Summarizing the evidence Data synthesis consists of tabulation of study characteristics, quality and effects as well as use of statistical methods for exploring differences between studies and combining their effects (meta-analysis). Exploration of heterogeneity and its sources should be planned in advance (Step 3). If an overall meta-analysis cannot be done, subgroup meta-analysis may be feasible Step 5: Interpreting the findings The issues highlighted in each of the four steps above should be met. The risk of publication bias and related biases should be explored. Exploration for heterogeneity should help determine whether the overall summary can be trusted, and, if not, the effects observed in high-quality studies should be used for generating inferences. Any recommendations should be graded by reference to the strengths and weaknesses of the evidence
How many hours does it take to write a systematic review?
How long does it take to do a systematic review? Systematic reviews are time intensive and require a lot of dedicated effort. They are not quick- systematic reviews can take anywhere from 6-18 months, depending on many different factors.
Can I write a systematic review by myself?
Systematic reviews cannot be performed alone. One investigator is not sufficient to reduce the risk of bias in the review process. 
It is essential that Cochrane reviews be undertaken by more than one person. This ensures that tasks such as selection of studies for eligibility and data extraction can be performed by at least two people independently, increasing the likelihood that errors are detected.
Include expertise in the pertinent clinical content areas Include expertise in systematic review methods Include expertise in searching for relevant evidence Include expertise in quantitative methods Include other expertise as appropriate
– National Academies of Sciences, Engineering, and Medicine, Finding What Works in Health Care: Standards for Systematic Reviews, chapter 2, 2011.
How many papers is enough for a systematic review?
What Is the Minimum Number of Studies to Include in a Systematic Review? – There is no minimum number of studies to include in a systematic review. The number of studies you include in a systematic review largely depends on your research topic, as well as the amount of supportive evidence available.
Can I do a systematic review in 3 months?
How long does it take to do a systematic review? – Systematic and scoping reviews typically require a year or more to complete. The Cochrane Collaboration has reported that comprehensive literature searches for systematic reviews may require 3 to 8 months for completion.
Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (editors). Cochrane Handbook for Systematic Reviews of Interventions version 6.2 (updated February 2021). Cochrane, 2021. Available from www.training.cochrane.org/handbook, Borah, R., et al. (2017). Analysis of the time and workers needed to conduct systematic reviews of medical interventions using data from the PROSPERO registry,
BMJ Open, 7(2), e012545.
Why is systematic review difficult?
The 5 most common mistakes to avoid when you are publishing a systematic review Systematic reviews are the answer to many challenges faced by researchers. While adding transparency to a study and saving resources by avoiding repetition, systematic reviews also offer unparalleled credibility to your research.
- Yet, more often than not, researchers make avoidable mistakes which keeps their hard work from getting published.
- To quote Paul Whaley, Associate Editor for systematic reviews for, 43 out of 46 systematic reviews fall at the first hurdle, and “it only takes two minutes to reject two years of researchers’ hard work.” “A systematic review answers a pre-defined research question by collecting and summarizing all the evidence that fits into a prespecified eligibility criteria.
It can be both qualitative or quantitative.” – Naomi Lee, Executive Editor for The Lancet For more information on systematic reviews see: https://researcheracademy.elsevier.com/writing-research/technical-writing-skills/systematic-reviews-101 Looking to unpack the issue, invited, Executive Editor for The Lancet and, to lead a live webinar discussing the basics of a systematic review. As well as covering techniques for ensuring a publishable systematic review, they also highlighted five common mistakes to avoid while writing one. Here’s what to watch out for according to our experts:
The topic has already been covered Systematic reviews are attempting to answer a very specific research question and will therefore be redundant if the topic has been covered already. Even if your review checks all other boxes, if the question you are attempting to answer has already been answered by other systematic reviews, and brings no new insights, it will not be publishable. Tip: Do your homework – are there other recent reviews covering this topic that have already answered your question? Do you have a sufficiently novel angle? Your literature search strategies have been poorly defined Systematic reviews are meticulous, well-planned, and exhaustive. If your literature search strategy has not been properly crafted and documented, transparently capturing all the literature which may be of relevance to answering your question, you are at high risk of producing biased results. Tip: Document all the search terms, study types, databases, and all the choices you make in your research to keep the search strategy valid. You failed to adequately assess the risk of bias Bias in research can skew the results of a study, and including biased studies in a systematic review can therefore undermine its validity. While, it can be very difficult to evaluate the extent to which a study is biased, authors of systematic reviews can assess the potential for the risk of bias. Tip: By invoking domain-specific methodologies, especially those which avoid the use of scores/scales, can help assess the risk of bias. Your interpretation of the strength of the evidence is unstructured or unsystematic Systematic reviews require a systematic assessment of the strength of scientific evidence which you synthesize in answering your research question. Your approach should be to identify issues which are important in determining confidence in your results (such as overall risk of bias in the evidence, heterogeneity of results, publication bias, etc.). The higher the quality of the material, the more reliable the results of your review will be. Similarly, the better your appreciation of the limits of the evidence base, the more valuable your review will be to other researchers. Tip: There are existing protocols and tools for assessing the level and strength of evidence of studies. Be sure to find the right one for your research and field. You didn’t plan enough in advance Systematic reviews are a complex, multi-step research tool which require you to bring together multiple skill-sets, many of which may not be familiar to you. There is a lot of help, with many textbooks, method papers and training courses which you will be able to draw upon. Take advantage of this when planning your protocol, and get expert advice from strategic review specialists on how to conduct your systematic review. Tip: If you intend to publish the results, you should seriously consider publishing your protocol – an option afforded by an increasing number of systematic review journals.
Is a systematic review hard?
A systematic review is a highly rigorous review of existing literature that addresses a clearly formulated question.
What is the minimum number of authors for a systematic review?
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.
Can a single person do a systematic review?
A systematic review cannot be conducted by one person. You need a team that includes: Subject experts with clinical and methodological expertise. Two people to review the results independently.
Can I do a systematic review in a month?
Over the past few years, there has been an explosion in the number of systematic reviews conducted and published — although a systematic review is an inappropriate or unnecessary research methodology for answering many research questions. Systematic reviews can be inappropriate for a variety of reasons:
The topic is too new and there aren’t enough relevant published papers to synthesise and analyse for a systematic review Many other people have already published systematic reviews on the topic (do a scoping search on the Cochrane Library, or by limiting your search results to systematic reviews on other databases, to see if other systematic reviews exist) You do not have enough time to conduct a systematic review (most systematic reviews will take between six to eighteen months on average to complete) You do not have any coauthors with whom to conduct the systematic review (systematic review methodology requires two authors to independently screen references to determine which fit pre-defined inclusion criteria)
If you feel your circumstances or research topic match any of the above, a systematic review may not be the best approach for you. You could still do a literature review, and adopt elements of systematic review methodology, rather than a systematic review.
What makes a good systematic review?
Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. A good SR also includes a comprehensive and critical discussion of the results, including strengths and limitations, such as assessment of bias, heterogeneity, and used definitions and categorizations.
Do you need two reviewers for systematic review?
The Value of a Second Reviewer for Study Selection in Systematic Reviews Res Synth Methods. Author manuscript; available in PMC 2020 Dec 1. Published in final edited form as: Res Synth Methods.2019 Dec; 10(4): 539–545. Published online 2019 Jul 18. doi: PMCID: PMC6989049 NIHMSID: NIHMS1040153 1 Division of Public Health Sciences, Department of Surgery, Washington University School of Medicine, Saint Louis, MO Find articles by 1 Division of Public Health Sciences, Department of Surgery, Washington University School of Medicine, Saint Louis, MO Find articles by 2 Brown School, Washington University School of Medicine, Saint Louis, MO Find articles by 3 Behavioral Research Program, Division of Cancer Control & Population Sciences, National Cancer Institute, Bethesda, Maryland Find articles by 3 Behavioral Research Program, Division of Cancer Control & Population Sciences, National Cancer Institute, Bethesda, Maryland Find articles by 1 Division of Public Health Sciences, Department of Surgery, Washington University School of Medicine, Saint Louis, MO Find articles by Although dual independent review of search results by two reviewers is generally recommended for systematic reviews, there are not consistent recommendations regarding the timing of the use of the second reviewer.
This study compared the use of a complete dual review approach, with two reviewers in the both the title/abstract screening stage and the full-text screening stage, as compared to a limited dual review approach, with two reviewers only in the full-text stage. This study was performed within the context of a large systematic review.
Two reviewers performed a complete dual review of 15,000 search results and a limited dual review of 15,000 search results. The number of relevant studies mistakenly excluded by highly experienced reviewers in the complete dual review was compared to the number mistakenly excluded during the full-text stage of the limited dual review.
In the complete dual review approach, an additional 6.6% to 9.1% of eligible studies were identified during the title/abstract stage by using two reviewers, and an additional 6.6% to 11.9% of eligible studies were identified during the full-text stage by using two reviewers. In the limited dual review approach, an additional 4.4% to 5.3% of eligible studies were identified with the use of two reviewers.
Using a second reviewer throughout the entire study screening process can increase the number of relevant studies identified for use in a systematic review. Systematic review performers should consider using a complete dual review process to ensure all relevant studies are included in their review.
When performing a systematic review, the importance of study selection cannot be overstated. Decisions about which studies to include are considered among the most significant decisions made during the review process., The quality of the study selection process is dependent on two factors, the formation of specific and clear eligibility criteria, and the systematic implementation of these criteria against each record found in the search process.
As a comprehensive search strategy can result in thousands of results that must be screened, the process of screening search results against eligibility criteria can require significant time and resources. The best method for study screening is one that allows for a high level of accuracy, ensuring that no relevant studies are mistakenly excluded, with as much efficiency as possible.
- Studies can be mistakenly excluded during the screening process due to a misapplication or misunderstanding of eligibility criteria or due to random error of the screener.
- In order to reduce this potential for missed studies, it is commonly recommended that two (or more) screeners undertake the screening process.
The Agency for Healthcare Research and Quality (AHRQ), the Center for Reviews and Dissemination (CRD), the Institute of Medicine (IOM), and the Cochrane Collaboration all recommend using two or more members of the review team, working independently, to screen studies.
The IOM specifically notes that doubling the number of screeners requires significant time and resources, but that the additional expense is justified in order to reduce bias and errors. A previous study explored the impact of using dual reviewers as compared to a single reviewer, and found that the average increase in eligible studies identified using two reviewers was 9%, ranging from 0% to 32%, suggesting a notable impact by the second reviewer.
Additionally, these groups are consistent in recommending that study screening be performed in a two-stage process, in which titles and abstracts are screened first, followed by full-text study reports. However, these groups do not explicitly recommend if the additional reviewer should be involved in both stages.
- Cochrane and AHRQ address this briefly.
- Cochrane suggests that adding a second reviewer at the full-text stage may be sufficient, saying that “Authors must first decide if more than one of them will assess the titles and abstracts of records retrieved from the searchIt is most important that the final selection of studies into the review is undertaken by more than one author.” AHRQ states that, “Some form of dual review should be done at each stage,” however they suggest alternatives to dual review in the title/abstract stage such as having the second reviewer only review the first reviewer’s exclusions, or only conducting dual review on a small percentage of the records in a pilot phase in order to resolve any confusion, and then going on to single review only for the remainder of the title/abstract phase.
However, while performing a pilot phase may help to reduce error due to unclear or misunderstood eligibility criteria, it is unlikely to prevent all error, and it will not prevent random error by the reviewer, so is unlikely to be sufficient to improve accuracy and prevent mistakenly excluded studies.
Using a second reviewer in the screening process represents a significant amount of resources. Using a second reviewer only in the full-text stage of screening may be a way to reduce resources necessary, while still maintaining a lower level of bias. A previous study explored various methods of study selection using a cost-effectiveness analysis and found that using two reviewers in the title/abstract stage and moving all records marked by at least one reviewer as eligible, rather than resolving disagreements, was equally effective and less costly than traditional double screening in a systematic review of effects of undergraduate medical education in UK general practice settings.
However, they conclude that effectiveness of different screening methods is likely to vary between systematic reviews. We set out to compare two methods of study selection, using dual independent reviewers throughout the title/abstract and full-text stages of the screening process versus using dual independent reviewers only in the full-text stage in the context of a systematic review exploring representation of multimorbidity in behavioral intervention randomized controlled trials.
The objective of this study is to identify if using dual reviewers throughout the entire study screening process produces a clear benefit over using dual reviewers only at the full-text screening stage in a large systematic review. This study took place in the context of a large systematic review evaluating the inclusion of participants with multiple chronic conditions in randomized trials of behavioral health interventions.
The methods and results of this systematic review are reported separately, but summarized briefly here. The eligibility criteria of the systematic review were (1) Primary report of a RCT testing the efficacy or effectiveness of behavioral interventions (2) the study reports original data (protocols, post-trial follow-up studies, secondary or separate subgroup analyses were excluded) (3) the RCT targets chronic illness (4) the RCT applied eligibility criteria at the individual level (5) the trial was published in English (6) the RCT enrolled only adult subjects (≥18 years).
The search strategy of the systematic review was designed to be broad in order to identify all published RCTs in adults that test behavioral health interventions and target chronic illness. Due to this broad search strategy, this systematic review involved a large number of search results which provided the ideal setting for the current study.
This search produced 343,123 records of potentially relevant reports. After removing duplicate records, 190,555 records remained. After the search was performed, a sampling strategy was used to produce a representative sample of literature of behavioral intervention RCTs targeting participants with chronic conditions published from 2000 to 2014.
This was done by randomly ordering search results (within three time periods, 2000–2004, 2005–2009, 2010–2014) using the RAND function in Microsoft Excel and performing study selection on the randomly ordered results within each time period until the target sample size (200 studies per time period, 600 studies total) was reached.
For purposes of the current study, the first 15,000 records from the randomly ordered search results (5,000 per time period) were used for the complete dual review approach and the next 15,000 records of the randomly ordered search results (5,000 per time period) were used for the limited dual review approach.
Two experienced reviewers (CS, SI) took part in this study. Both reviewers were involved in the study design of the systematic review and the definition of the eligibility criteria. The reviewers went through a pilot process with the eligibility criteria prior to starting the study to ensure they had a similar understanding of the eligibility criteria.
During the first approach of the study (), reviewers fully performed a dual independent review of all records. Reviewers first independently screened studies by title/abstract and compared results. Records were excluded if both reviewers had excluded them.
- Records were moved to full-text screening if both reviewers indicated they should be kept.
- Records for which reviewers had opposing decisions were reviewed again together and a consensus was made to exclude them or move them to full-text screening.
- Reviewers then independently screened identical lists of studies by reading the full-text of each study report and applying eligibility criteria.
After the screenings were complete, results were compared. Records were excluded if both reviewers had excluded them. Records were included in the review if both reviewers had included them. Records for which reviewers had opposing decisions were reviewed again together and a consensus was formed.
This review process was completed in three sets of 5,000 records (total of 15,000 records), with comparison between the results of the two reviewers at the end of each set. In the second approach of the study (), reviewers performed a limited dual review of records. Records were assigned to each reviewer in alternating groups of 2,500 (total of 15,000 records) such that each title/abstract was reviewed by only one reviewer.
Decisions made by the sole reviewer regarding exclusion or moving of the record to full-text screening were considered final. Studies indicated for full-text review by solo review were then independently dually reviewed, following the same full-text review process as in the first approach of the study.
How much does it cost to publish a systematic review?
Article-processing charges – Open access publishing is not without costs. Systematic Reviews therefore levies an article-processing charge of £1990.00/$2790.00/€2290.00 for each article accepted for publication, plus VAT or local taxes where applicable.
- If the corresponding author’s institution participates in our open access membership program, some or all of the publication cost may be covered (more details available on the membership page ).
- We routinely waive charges for authors from low-income countries,
- For other countries, article-processing charge waivers or discounts are granted on a case-by-case basis to authors with insufficient funds.
Authors can request a waiver or discount during the submission process. For further details, see our article-processing charge page, Visit Springer Nature’s open access funding & support services for information about research funders and institutions that provide funding for APCs.
- Springer Nature offers agreements that enable institutions to cover open access publishing costs.
- Learn more about our open access agreements to check your eligibility and discover whether this journal is included.
- For more information on APCs please see our Journal Pricing FAQs Systematic Reviews is involved in a pilot study of new technology enabling the setting of article processing charges (APCs) at an article-type level within a journal instead of charging at a flat rate.
APCs on this journal are as follows for the duration of the pilot:
| Article type | APC GBP* | APC EUR* | APC USD* |
| Research | £1990 | €2290 | $2790 |
| Protocol | £1990 | €2290 | $2790 |
| Methodology | £1990 | €2290 | $2790 |
| Commentary | £1010 | €1145 | $1380 |
| Letter | £1010 | €1145 | $1380 |
| Systematic Review Update | £1010 | €1145 | $1380 |
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Is A systematic review quantitative or qualitative?
Presentation of Results – Finally, once the data is analyzed, the results of the reviews or studies are presented accordingly. For qualitative research, the results are explained as a textual summary that corroborates all the findings of the study. Quantitative studies express the results in the form of numbers and graphs. (Article continues below) Both qualitative and quantitative research approaches provide different kinds of knowledge. A systematic review can be qualitative, quantitative, or a combination of the two. The approach that is chosen is determined by the research question and the scope of the research.
When qualitative and quantitative techniques are used together in a given study, it is called a mixed method. In a mixed-method study, synthesis for the quantitative and qualitative studies should be done separately then the integration of the qualitative and quantitative results by investigating whether the qualitative results can help explain the quantitative results.
Most systematic reviews require a certain degree of statistical support using meta-analysis. By including meta-analysis, you can reduce the possibility of introducing bias in the systematic review. To know more about the, click this link. Resources & Industry insights Systematic Review Best Practices : Are Systematic Reviews Qualitative or Quantitative
What are 2 key features of a systematic review?
The key characteristics of a systematic review are: a clearly defined question with inclusion & exclusion criteria ; rigorous & systematic search of the literature; critical appraisal of included studies; data extraction and management; analysis & interpretation of results; and report for publication.
Can you repeat a systematic review?
However, the rationale for repeating a systematic review/meta-analysis should be stated explicitly. The manuscript should include what is already known from previous reviews and what this current review adds.
What are the stages of a systematic review?
Systematic review/meta-analysis steps include development of research question and its validation, forming criteria, search strategy, searching databases, importing all results to a library and exporting to an excel sheet, protocol writing and registration, title and abstract screening, full-text screening, manual
What are the key elements of a systematic review?
The key characteristics of a systematic review are: a clearly defined question with inclusion & exclusion criteria; rigorous & systematic search of the literature; critical appraisal of included studies; data extraction and management; analysis & interpretation of results; and report for publication.
What are the 4 phases of systematic procedure?
This four-phase model encompasses four interdependent but connecting sub-processes, namely: needs assessment (situation analysis), planning (programme design), implementation and evaluation.
What are the 4 phases of systematic procedure in research?
Research is a dynamic process that can be organized into four stages: Exploring, Investigating, Processing, and Creating.