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Purpose: To examine the concepts of external validity and generalizability, and explore strategies to strengthen generalizability of research findings, because of increasing demands for knowledge utilization in an evidence-based practice environment.
Framework: The concepts of external validity and generalizability are examined, considering theoretical aspects of external validity and conflicting demands for internal validity in research designs. Methodological approaches for controlling threats to external validity and strategies to enhance external validity and generalizability of findings are discussed.
Conclusions: Generalizability of findings is not assured even if internal validity of a research study is addressed effectively through design. Strict controls to ensure internal validity can compromise generalizability. Researchers can and should use a variety of strategies to address issues of external validity and enhance generalizability of findings. Enhanced external validity and assessment of generalizability of findings can facilitate more appropriate use of research findings.
JOURNAL OF NURSING SCHOLARSHIP, 2004; 36:1, 16-22. (©2004 SIGMA THETA TAU INTERNATIONAL.
[Key words: external validity, generalizability, research utilization, knowledge utilization]
Although nursing research has reduced the gap between theory and practice, the gap persists (Chinn & Kramer, 1999; Schmitt, 1999). Practitioners often report that the findings of research studies are difficult to use in practice, or are irrelevant to their practice issues, or are inaccessible to practitioners (Estabrooks, 1998; Huberman, 1995; Lomas, 2000). Researchers bemoan the lack of use of their study results in practice, despite efforts to disseminate findings (Huberman, 1995; Landry, Amara, & Lamari, 2001; Lomas, 2000; Rich, 1991). This disparity between nursing researchers and practitioners is evidence of the continuing challenge to link theory, research, and practice.
The main premise of this article is that an increased focus on external validity of studies and generalizability of findings could increase the use of knowledge generated in those studies. External validity can be viewed as the conceptual as well as the effective link between knowledge generation and knowledge utilization. Researchers should design and report their studies with reasonable generalization of findings as a goal.
The topic of external validity is largely absent in nursing literature. A search of CINAHL between 1982 and 2002 revealed no nursing articles and only three editorials dealing with external validity or generalizability as the main focus (Hayes, 1998; Hegyvary, 2002; Schmitt, 1999). Researchers need specific...