Skip Navigation
Department of Health and Human Services www.hhs.gov
 
Slide Tray
0 slides

Return to Slide Library

Slides

Add Search Results to Slide Tray Search:

"statistical methods"

Slides: 1–12 of 12
On Data Extraction (II). Data extraction involves more than copying words and numbers from the publication to a form. Clinical domain, methodological, and statistical knowledge is needed to ensure the right information is captured. Interpretation of published data is often needed. What is reported is sometimes not what was carried out. Data extraction and evaluation of risk of bias and of applicability typically occur at the same time.

On Data Extraction (II)

This slide presents a table consisting of four columns. Column one is unlabeled; column two is labeled “Odds Ratio,”column three is labeled “Risk Ratio,” column four is labeled “Risk Difference.” Data row one, “Fixed Effect Model.” Odds ratio: Mante, 1-HaenszelPeto, Exact, Inverse variance weighted; Risk Ratio: Mantel-Haenszel, Inverse variance weighted; Risk Difference: Inverse variance weighted. Data row two, “Random Effects Model.” Odds ratio: DerSimonian and Laird. ; Risk Ratio: DerSimonian and Laird; Risk Difference: DerSimonian and Laird.

Commonly Used Statistical Methods for Combining 2x2 Tables

This figure shows a meta-regression plot. Studies are depicted as empty circles with areas proportional to their weight (influence). A line describes how the treatment effect (risk of all-cause death, y-axis) changes with the dose of vitamin E supplementation (x-axis). The line curves upward for higher doses, suggesting increased risk of death with increasing dose.

Corresponding Univariate Meta-Regression: A Meta-analysis of Vitamin E Doses and Mortality

Confounding by Indication. Is a type of selection bias. Occurs when different diagnoses, severity of illness, or comorbid conditions are important reasons for physicians to assign different treatments. Is a common problem in pharmacoepidemiological studies comparing benefits. Is often difficult to adjust for, making studies with a high degree of this potential bias usually unsuitable for inclusion in a comparative effectiveness review.