Alaryhmäanalyysin

Alaryhmäanalyysi, known in English as subgroup analysis, is a statistical method used in research, particularly in clinical trials and observational studies, to examine how treatment effects or relationships between variables differ across various subgroups of the study population. Instead of looking at the overall effect of an intervention or association, researchers perform separate analyses for specific predefined groups. These groups are typically defined by characteristics such as age, sex, disease severity, genetic markers, or geographical location.

The primary purpose of alaryhmäanalyysi is to explore potential heterogeneity in treatment effects or associations. It can help identify if a treatment is more or less effective in certain patient populations, or if a risk factor has a stronger impact on specific demographic groups. This can lead to more personalized treatment strategies or a better understanding of disease mechanisms.

However, alaryhmäanalyysi must be interpreted with caution. Conducting multiple subgroup analyses increases the risk of false-positive findings due to multiple comparisons. If subgroups are not prospectively defined in the study protocol, the analyses are considered post hoc and are more prone to finding spurious associations. Therefore, statistically significant results from subgroup analyses should generally be considered hypothesis-generating rather than definitive proof, and should ideally be confirmed in subsequent studies. The validity of subgroup analyses also depends on adequate sample sizes within each subgroup to ensure sufficient statistical power.