forestplotissa

Forestplotissa is a term used in Finnish statistical literature to refer to a forest plot, a graphical display commonly employed in meta-analysis to summarize estimated effects across multiple studies and the overall pooled result. In a typical forest plot, each row represents a single study, showing the study’s effect estimate as a square and its confidence interval as a horizontal line. The size of the square often reflects the study’s weight in the meta-analysis. A vertical line marks the null effect (for example, an odds ratio of 1 or a zero difference), against which other estimates are compared. The overall pooled effect is usually shown as a diamond at the bottom of the plot, with the diamond’s width representing the confidence interval for the pooled estimate.

Interpreting a forest plot involves examining the direction and magnitude of individual study estimates, the precision of those estimates, and the position of the pooled effect relative to the line of no effect. If a study’s confidence interval crosses the null line, it is not statistically significant at the chosen level. If the diamond does not cross the null line, the overall effect is considered statistically significant. Forest plots can also illustrate heterogeneity among studies and are often produced with different meta-analytic models, such as fixed-effect or random-effects, which influence study weights and the pooled result.

Usage and limitations: forest plots summarize evidence from multiple studies in a compact form and aid interpretation, but they rely on the quality of included studies and the chosen effect measure. Potential biases (publication bias, selective reporting) and between-study heterogeneity should be considered when drawing conclusions. Forest plots became widely used in medical research and Cochrane reviews in the late 20th century.