Generalizability

← Back to Glossary

Definition

Generalizability refers to how well the results of a study can be applied to people, settings, and conditions beyond those that were directly studied. It reflects whether conclusions drawn from a specific sample can reasonably extend to a broader population.

Correct Scientific Usage

Researchers assess generalizability by comparing study populations to target populations. Well-designed studies explicitly describe their population characteristics and acknowledge limitations to generalizability.

A study with high internal validity may still have limited generalizability if its participants differ meaningfully from real-world patients in age, sex, health status, genetics, or environment.

Common Misunderstandings

Study results are often assumed to apply universally when they may only apply to specific groups. Randomized controlled trials are often treated as universally applicable by default, but even rigorous trials can have limited generalizability.

Why It Matters

Understanding generalizability prevents misapplying findings to inappropriate populations. It explains why a treatment may be effective in one group, but not in another, and why careful consideration of study populations is essential when evaluating whether evidence applies to you.

References

  • Evidence for Health Decision Making — Beyond Randomized, Controlled Trials, NEJM
  • Generalizability: Linking Evidence to Practice, JOSPT

← Back to Glossary