External validity

External validity is the validity of applying the conclusions of a scientific study outside the context of that study.[1] In other words, it is the extent to which the results of a study can generalize or transport to other situations, people, stimuli, and times.[2][3] Generalizability refers to the applicability of a predefined sample to a broader population while transportability refers to the applicability of one sample to another target population.[2] In contrast, internal validity is the validity of conclusions drawn within the context of a particular study.

Mathematical analysis of external validity concerns a determination of whether generalization across heterogeneous populations is feasible, and devising statistical and computational methods that produce valid generalizations.[4]

In establishing external validity, scholars tend to identify the "scope" of the study, which refers to the applicability or limitations of the theory or argument of the study.[2] This entails defining the sample of the study and the broader population that the sample represents.[2]

  1. ^ Mitchell, M. & Jolley, J. (2001). Research Design Explained (4th Ed) New York:Harcourt.
  2. ^ a b c d Findley, Michael G.; Kikuta, Kyosuke; Denly, Michael (2021). "External Validity". Annual Review of Political Science. 24 (1): 365–393. doi:10.1146/annurev-polisci-041719-102556. ISSN 1094-2939.
  3. ^ Aronson, E., Wilson, T. D., Akert, R. M., & Fehr, B. (2007). Social psychology. (4 ed.). Toronto, ON: Pearson Education.
  4. ^ Pearl, Judea; Bareinboim, Elias (2014). "External validity: From do-calculus to transportability across populations". Statistical Science. 29 (4): 579–595. arXiv:1503.01603. doi:10.1214/14-sts486. S2CID 5586184.