What if a study is not statistically significant?
If the result is not statistically significant, adequate sample size and power increase the likelihood that the study can still contribute to the body of knowledge, because a well-designed study offers respectable evidence that a clinically important effect is absent.
What is the goal of 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.
Are there any problems with a meta-analysis?
A well-done meta-analysis of badly designed studies will yield invalid results. Bias and confounding in the primary studies are major problems for meta-analysis, notably, issues of randomization and blinding in clinical trials.
Which is the highest level of evidence in a meta analysis?
If the individual studies utilized randomized controlled trials (RCT), combining several selected RCT results would be the highest-level of evidence on the evidence hierarchy, followed by systematic reviews, which analyze all available studies on a topic. Greater statistical power Confirmatory data analysis
Which is more accurate, a meta-analysis or a primary study?
Mathematically combining data from a series of well-conducted primary studies may provide a more precise estimate of the underlying “true effect” than any individual study ( 28 ).
Is there a publication bias in a meta-analysis?
Publication bias is likely to lead to overestimation of the true effect in meta-analysis. Another meta-analysis on the effect of acetylcysteine for prevention of contrast nephropathy [ 19] revealed a suspected publication bias in the absence of smaller studies from the funnel plot and confirmed this with a statistical test.