External Validity

Definition

External validity refers to the extent to which research findings can be generalized to, or have relevance for, settings, people, times, and measures outside of the specific conditions of the study. It focuses on how well the results of a study can apply to real-world situations and different populations, which is crucial for establishing broader implications of research findings.

5 Must Know Facts For Your Next Test

1. External validity is essential for determining whether research findings can be applied to different groups or environments beyond those studied.
2. In experiments, controlling variables can enhance internal validity but may limit external validity if the study conditions are too artificial.
3. Quasi-experiments often have lower external validity than true experiments due to less control over variables and potential biases in sample selection.
4. Different sampling methods can significantly impact external validity; random sampling tends to enhance generalizability, while convenience sampling can limit it.
5. Research designs like multiphase designs may incorporate various populations or settings, enhancing external validity by demonstrating applicability across different contexts.

Review Questions

• How does external validity influence the conclusions that can be drawn from experimental research?
  • External validity plays a critical role in determining how well the results of an experiment can be generalized beyond the specific conditions under which it was conducted. If an experiment has high external validity, researchers can confidently apply their findings to broader contexts, populations, or settings. Conversely, if an experiment lacks external validity, the conclusions may only be relevant to the study's sample and conditions, limiting their usefulness in real-world applications.
• Compare and contrast external validity in experiments versus quasi-experiments and explain how this impacts research conclusions.
  • In experiments, researchers typically have more control over variables, which helps enhance internal validity but may come at a cost to external validity due to artificial settings. Quasi-experiments often take place in more natural environments but lack random assignment, making it harder to control for confounding variables. As a result, quasi-experimental findings may have better external validity because they reflect real-world situations, but they might also contain biases that affect their reliability compared to tightly controlled experimental outcomes.
• Evaluate how different sampling methods impact external validity and discuss strategies researchers might use to improve generalizability.
  • Sampling methods greatly influence external validity since they determine how representative a study's sample is of the broader population. Random sampling increases generalizability by ensuring every individual has an equal chance of being selected, while convenience sampling may limit this ability by drawing from easily accessible participants. To improve external validity, researchers can use stratified sampling techniques to include diverse subgroups or replicate studies in various contexts or with different populations to strengthen confidence in their findings' applicability.

Related terms

Generalizability: The ability to apply findings from a study to larger populations beyond the sample used in the research.

Ecological Validity: The degree to which the findings of a study can be applied to real-world settings and situations, emphasizing the naturalness of the environment in which the research is conducted.

Sample Representativeness: The extent to which a sample reflects the characteristics of the larger population it represents, impacting the generalizability of research results.