This document explains the role of randomized controlled trials (RCTs) in meta-analysis, highlighting their importance in assessing the efficacy of interventions through systematic reviews. It discusses the process of identifying relevant RCTs, data extraction, calculating effect sizes, and addressing issues like publication bias and heterogeneity. The final analysis provides a comprehensive evaluation of treatment effects, which is crucial for deriving reliable conclusions in scientific research.

1. How Randomized Controlled
Trials are Used in Meta-
Analysis
An Academic presentation by
Dr. Nancy Agnes, Head, Technical
Operations, Pubrica
Group: www.pubrica.com
Email: sales@pubrica.com

2. • Randomized controlled trials (RCTs) are prospective studies that assess the efficacy of a
novel intervention or treatment.
• Although no research is likely to show causation, randomization eliminates bias and provides
a rigorous technique for examining cause-effect correlations between an intervention and
result.
• This is because the process of randomization balances participant characteristics (both
observable and unobserved) between groups, allowing any variations in result to be
attributed to the research intervention. This is not achievable with any other research design.
Introduction
Randomized controlled trials—for efficacy research

3. • Randomized Controlled Trials (RCTs) are a commonly used research design in medical and scientific
studies to assess the effectiveness of interventions or treatments. Meta-analysis, on the other hand, is a
statistical technique used to combine and analyze the results of multiple studies on a particular topic to
draw more robust conclusions.
• To know more about meta-analysis services, check our study guide on How to do a meta-analysis for a
manuscript.
RCTs areUsed inMeta-Analysis

5. • The first step in a meta-analysis is to
identify all relevant RCTs that have
been conducted on a specific topic.
This is typically done through a
systematic literature review, where
researchers search various databases
and sources to find all available RCTs.
• Researchers establish specific inclusion
and exclusion criteria to determine
which RCTs are eligible for inclusion in
the meta-analysis. Common criteria
might include the type of intervention,
the patient population, the outcome
measures, and the study design.
Identifying
Relevant RCTs
1
2
InclusionCriteria
Here's how RCTs are used in the context of
meta-analysis

6. • For each eligible RCT, relevant data is
extracted. This includes information
about the study design, sample size,
treatment group, control group, and the
results in terms of the outcome of
interest. This data collection is typically
recorded in a standardized format.
• One of the key steps in meta-analysis is
calculating the effect size for each RCT.
The effect size is a measure of the
magnitude of the treatment effect, and
it allows for the comparison of results
across different studies. Common effect
size measures include odds ratios, risk
ratios, or mean differences, depending
on the type of data and outcome being
studied.
Data Extraction
3
4
Effect Size
Calculation

7. • In a meta-analysis, not all studies are
given equal importance. Larger studies
or those with a lower risk of bias may be
given more weight in the analysis. This
helps ensure that the results of higher-
quality studies have a greater influence
on the overall findings.
• Meta-analysis employs statistical
techniques to combine the effect sizes
from individual RCTs. A common
method is to use a weighted average of
the effect sizes, where the weights are
determined by the study's sample size
and quality.
WeightingStudies
5
6
StatisticalAnalysis:

8. • Researchers assess the heterogeneity
of the included RCTs to determine how
much variability exists between the
studies. This is important because high
heterogeneity may impact the
reliability of the meta-analysis results.
• Publication bias occurs when studies
with positive results are more likely to be
published, leading to an overestimation
of the treatment effect. Meta-analysts
often assess for publication bias and
attempt to correct it.
Heterogeneity
Assessment
7
8
PublicationBias
Assessment

9. • The meta-analysis results are
interpreted to provide an overall
estimate of the treatment effect, along
with a measure of uncertainty (e.g., a
confidence interval). This synthesis of
evidence from multiple RCTs allows for
a more comprehensive and reliable
assessment of the intervention's
efficacy.
• Check our Examples to get an understanding of our adaptability across
meta-analysis topics and subject domains.
• The findings of the meta-analysis are
typically reported in a scientific paper or
a report, and they may be subject to
peer review and publication in
academic journals.
Interpretationof
Results
9
10
Reporting and
Publication

10. • Pubrica has extensive experience in conducting meta-analysis, a quantitative, formal,
epidemiological study design used to systematically assess the results of previous research to derive
conclusions about that body of research.
• Pubrica's team of researchers and authors develop Scientific and medical research papers that can
act as an indispensable tool to the practitioner/authors.
• Pubrica medical writers help you to write and edit the introduction by introducing the reader to the
shortcomings or empty spaces in the identified research field.
• Our experts are aware of the structure that follows the broad topic, the problem, and the background
and advance to a narrow topic to state the hypothesis.
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