Forest plot interpretation

Question 1

What does a forest plot display?

Answer 1

Effect estimates and confidence intervals for both individual studies and meta-analyses

A forest plot is a graphical representation commonly used in meta-analyses.

Question 2

How is each study represented in a forest plot?

Answer 2

By a block at the point estimate of intervention effect with a horizontal line extending either side of the block

This representation helps visualize the effect size and its uncertainty.

Question 3

What does the area of the block in a forest plot indicate?

Answer 3

The weight assigned to that study in the meta-analysis

Larger blocks typically indicate studies contributing more to the overall analysis.

Question 4

What does the horizontal line in a forest plot depict?

Answer 4

The confidence interval (usually with a 95% level of confidence)

This interval shows the range of values within which the true effect is likely to lie.

Question 5

What information do the area of the block and the confidence interval convey in a forest plot?

Answer 5

Both convey similar information but make different contributions to the graphic

The block size highlights studies with larger weight, while the confidence interval shows the range of possible effects.

Question 6

What does the confidence interval in a forest plot depict?

Answer 6

The range of intervention effects compatible with the study’s result

A narrower confidence interval indicates more precise estimates.

Question 7

What does the size of the block in a forest plot draw attention to?

Answer 7

Studies with larger weight, usually those with narrower confidence intervals

These studies are more influential in calculating the summary result.

Question 8

What is presented as a diamond at the bottom of a forest plot?

Answer 8

The summary result of the meta-analysis

This diamond represents the overall effect estimate across all studies included in the analysis.