HLTH 200 Lecture Notes - Lecture 6: Internal Validity, Quasi, Random Assignment
Document Summary
Researcher does not randomly assign people into groups. How does random selection differ from random assignment? (very important!!!!) Random selection: how you draw the sample of people for your study from a population, impacts external validity, helps insure that the sample is representative of the population (and hence, findings are more generalizable) Research substitutes statistical controls for a naturally unexposed or some other control group because they cannot control the experimental situation. Participants cannot be randomly assigned to either the experimental or the control group. The researcher cannot control which group will get the treatment. Participants do not have the same chance of being in the control or the experimental groups, or of receiving or not receiving the treatment. Comparison group: some other treatment or a different level of treatment. If yes, then it is a good idea to have different groups in the design that are based on dose.
