The effective sample size for a particular treatment comparison can be interpreted as the
number of patients in
a pairwise meta-analysis that would provide the same degree and strength of evidence as that which is provided in the indirect comparison or network meta-analysis.
What is an example of a meta-analysis?
For example, a systematic review will focus specifically on the relationship between
cervical cancer and long-term use of oral contraceptives
, while a narrative review may be about cervical cancer. Meta-analyses are quantitative and more rigorous than both types of reviews.
What is a good sample size for a meta-analysis?
The ideal number of studies in meta-analyzes is in the range of
20 to 30 effect sizes
, although it may contain many more.
What is sampling error in meta-analysis?
Sampling error is
a critical issue in meta-analyses
. … This method is generally valid when the number of samples within each collected study is large: the large-sample statistical properties, such as the central limit theory and the delta method, guarantee that the distribution approximation performs well.
What should a meta-analysis include?
The steps of meta analysis are similar to that of a systematic review and include
framing of a question, searching of literature, abstraction of data from individual studies
, and framing of summary estimates and examination of publication bias.
How many studies are enough for a meta-analysis?
Two studies
is a sufficient number to perform a meta-analysis, provided that those two studies can be meaningfully pooled and provided their results are sufficiently ‘similar’.
What is the main purpose of a meta-analysis?
Meta-analyses are conducted
to assess the strength of evidence present on a disease and treatment
. One aim is to determine whether an effect exists; another aim is to determine whether the effect is positive or negative and, ideally, to obtain a single summary estimate of the effect.
How do you write a good meta-analysis?
- Rule 1: Specify the topic and type of the meta-analysis. …
- Rule 2: Follow available guidelines for different types of meta-analyses. …
- Rule 3: Establish inclusion criteria and define key variables. …
- Rule 4: Carry out a systematic search in different databases and extract key data.
How meta-analysis is done?
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 types of meta-analysis?
- Meta- Analysis.
- Systematic. Review.
- Practice. Guideline.
- Randomized. Controlled Trial.
- Cohort Study.
- Case Control Study.
- Case Reports.
Does sample size affect bias?
Increasing the sample size tends to reduce the sampling error; that is, it makes the sample statistic less variable. However,
increasing sample size does not affect survey bias
. A large sample size cannot correct for the methodological problems (undercoverage, nonresponse bias, etc.)
What is an adequate sample size for systematic review?
When assessing whether sample sizes were adequate, the majority of studies (90-98%) were well powered to detect large effect sizes (2.0 SD) for one mean. However, few studies were adequately powered to detect smaller (and arguably more realistic) effect sizes (
0.2-1.0 SD
).
What is the problem with small sample size?
A sample size that is too small
reduces the power of the study and increases the margin of error
, which can render the study meaningless. Researchers may be compelled to limit the sampling size for economic and other reasons.
How long does a meta-analysis take?
They estimated it should take from
25 to 2,518 hours
, with a mean total of 1,139 hours, to conduct a meta-analysis. Their estimate included 588 hours needed for search, retrieval, and creation of a database for the search results. At the low end of the time spectrum, Saleh et al.
When should a meta-analysis not be used?
Meta-analyses of studies that are
at risk of bias
may be seriously misleading. If bias is present in each (or some) of the individual studies, meta-analysis will simply compound the errors, and produce a ‘wrong’ result that may be interpreted as having more credibility.
How do I know if I can do a meta-analysis?
When studies are addressing the same outcome, measured in the same way, using the same approach to analysis, but presenting results in different ways, then the only obstacles to meta-analysis are practical.
If sufficient information is available to estimate the effect size of interest
, then a meta-analysis is possible.
