How to Do a Meta-Analysis
Meta-analysis refers to a statistical technique used to combine data from multiple studies concerning a particular topic. Meta-analysis is an essentially systematic review. In addition to the narrative summary conducted in a systematic review in meta-analysis, the results of the studies and arrival at a summary are estimated and numerically pooled by analysts. At WOWGrade.net, we not only help you with your assignment but also teach you how to write a meta-analysis paper.
Systematic review and meta-analysis statistical tools review researches performed on the same topic, extracting the collective effect of the studies conducted after the statistical analysis of the data of all the studies included. WOWGrade.net teaches students how to write a meta-analysis dissertation.
With Systematic reviews and meta-analysis getting more popular in the medical field, statistics is never a strong aspect concerning medical professionals. Facing a large number of values and statistical tests could be quite confusing for them.
Difference between Systematic Review and Meta-analysis
Meta-analysis process of integration of the results of various studies helps one to arrive at evidence synthesis. WOWGrade.net will thus discuss the key steps of conducting a meta-analysis, demonstrating the various key steps from a published paper on meta-analysis as well as the systematic review. Below are nine steps on how to write a meta-analysis research paper.
- Framing a Question
Formulate a clear, concise and well-defined research question of appropriate scope, defining your terminology. Research on the existing reviews on your topic, which will inform the development of your research question. Ensure that you frame a good question which is your first big step on how to conduct a meta-analysis. Identifying gaps, confirm that you are not plagiarizing or duplicating the works of previous reviews.
To frame an answerable question in meta-analysis, you can use the PICO framework which is an acronym for ‘Participant-Intervention-Comparator-Outcomes’. ‘Participants’ in this context is the individuals of interest to us. For instance, if the interest is in the effectiveness of a drug among say adult asthma patients, you only include adult asthmatics and not older adults or children. PICO will help on how to write a meta-analysis research question effectively.
- Conducting a Search of the Literature Databases
Once you have decided on the PICO, do a proper search of the literature databases to help you identify the appropriate search terms. The search terms are usually arranged using fuzzy logic, Boolean Logic, specific search controlled vocabulary related, symbols of expansion or truncation, as well as the placement of the specific terms in various sections of a reported study.
To know how to do a meta-analysis literature review, run your searches in the databases which you have identified to be relevant to your topic. You can work with a librarian to assist you to design comprehensive search strategies across various databases. Purposefully approaching the gray literature methodically will help you know how to write a meta-analysis, collecting every retrieved record from each search into a reference manager, like Endnote, de-duplicating the library before screening.
- Selecting the Articles for Meta-Analysis Through Reading Titles, Abstracts and Full Texts
Starting with a title or abstract screening, remove studies which are not related to your topic. We advise using your inclusion or exclusion criteria to screen the full-text of your studies. WOWGrade.net highly recommends two independent reviewers to screen all studies and to resolve areas of disagreement by consensus.
Set up a scheme upon which will guide you on how to write a systematic review and decide on what articles to select and reject for your meta-analysis. For example, you can use a scheme which includes if the article is irrelevant for the study question, if it doesn’t have the relevant population or the proper exposure, or lacks an appropriate comparison group if it does not discuss an outcome of interest to the research, etc.
Even if a study has been rejected on two clauses, the first which rejects it is the main clause of rejection. You can use PRISMA (Preferred Reporting Items of Systematic Reviews and meta-analyses) chart to put to indicate which articles were rejected and why.
Then read the full text once more, conducting this rejection exercise and noting the numbers. Read the full text, hand searching the reference lists of these articles which will widen your research. Find out sources you must seek, identifying authors whose work you need to read to get a full list of every works and research which have been previously conducted.
- Abstracting Information From the Articles
After finding out the set of studies you will work with, you need to abstract data from them for your research. At the minimum, it is vital to obtain the information such as the name of the first author, year of publishing, the population, type of research whether observational, comparison condition, outcome and how was it measured, number of individuals in the intervention, and such related factors.
- Determining the Quality of Information of the Articles
Clearly presenting your findings, including detailed methodology, perform a meta-analysis if the studies allow. Provide recommendations for policy-making and practice if sufficient, existence of high-quality evidence, future directions for research to strengthen the body of evidence.
For each study, critically appraise the information and decide if the study meets the internal validity criteria. At the minimum, you need to highlight what the theory is about and the hypotheses. Ask yourself if the research is underpowered, the extent to which the authors eliminate biases in the study, how confident you are that authors conducted an appropriate randomization procedure, and so on.
A great way on how to write a systematic review to ascertain the quality of each article is the use of GRADE (Grading, recommendations assessment, development, and evaluation) criteria and use the GRADEpro software to judge the quality of the outcome-intervention pairing.
- Determining the Extent to Which the Articles are Heterogeneous
Think about the difference between systematic review and meta-analysis. A systematic review analysis follows the steps of framing a question, searching, identifying the right type of research and extracting information from the articles. All studies fit for inclusion in the review are summarized and patterns of information itemized and tabulated. This means that all study findings for a set of outcomes and interventions are identified, classified and discussed in systematic reviews.
In the meta-analysis definition, it is a scientific method and an implicit assumption that studies result from a population which is reasonably uniform across the intervention and outcomes exists. This indicates that either the body of the studies are exhaustive with the estimates between the exposures, or intervention and outcome are based on the evidence you identified and estimated the true association.
- Estimating Summary Effect Estimate
You need to determine the summary effect estimate assuming fixed and random effects model, then construct a Forest Plot which visually inspects how the effect estimates of every individual study is distributed around a zero value but as well around the overall effect estimates.
- Assessing Publication Bias
After identifying the heterogeneity of the studies and the summary effect estimate and forest plot, test whether there are biases which can impact the study conclusions. Test if your meta-analysis omits studies which should have been included. If a study is based on a large sample size with reported positive findings of an experiment, such a study possesses a higher chance of getting published and being identified through searches as compared to a study which is small and has reported negative findings or equivocal.
- Running Meta-Regression and Subgroup Analyses
After examining the heterogeneity of your studies, estimating the summary effect size, plotting the forest plot, and testing for publication bias, comment on the association between the intervention and the outcome.
The above guidelines will also help you know how to do a meta-analysis research on neurofeedback. There is no need for you to struggle with your meta-analysis assignments, since WOWGrade.net professional writers offer professional writing help, delivering great content on meta-analysis which will not only help you get good grades but will also help you know how to do a meta-regression in SPSS for a meta-analysis.