SOCI 200 Lecture Notes - Lecture 5: Internal Validity, Gastown
Document Summary
This aspect of validity relates to the degree that research findings (from a sample) can be generalized or extended to (1) the population or (2) similar contexts. Aspects of the sample are critical when evaluating external validity. Recall that aspects of the research design and in particular the research method are critical when evaluating internal validity. We will review three sampling approaches that affect external validity: probability sampling. In this approach, you must begin by identifying a population. You can mathematically calculate the probability that your sample is representative of your population. For example, 500 objects or people are defined in your population. So the probability that your sample is representative of the population is 20%. The higher the percent; the greater the external validity. This is why sample size affects external validity: random sampling. If you randomly select a sample from a defined population, this increases external validity as well.
