external validity

• a study has internal validity when...

  it measures what it claims to measure and there are no extraneous variables
• a study has external validity when...

  the results generalise to other situations and people
• what is ecological validity?

  The results of a study generalise to how people behave in everyday life.
• three types of external validity:

  1. ecological validity
  2. temporal validity
  3. population validity
• a study has temporal validity when...

  the results generalise over time
• a study has population validity when...

  Population validity is when the results of a study generalise to the rest of the population that the researcher wants to study.

  Population validity is higher when the sample includes multiple subgroups from the population.