MCS 3030 Chapter Notes - Chapter 8: Internal Validity

• School: University of Guelph
• Department: Marketing and Consumer Studies
• Course: MCS 3030
• Professor: Tanya Mark

Document Summary

1 group gets treatments/program (the x) and the other doesn"t. Experimental designs are usually considered the strongest of all designs in internal validity b/c internal validity is at the center of all causal or cause-effect inferences. If you are able to provide evidence for both propositions, (if x, then y & if not x, then not y), than you"ve in effect isolated the program from all the other potential causes of the outcome. In the simplest type of experiment, you create 2 groups that are equal to eachother. One group gets the program, and the other doesn"t. In all other respects the groups are treated the same. Now if you see differences in outcomes between the 2 groups, they must be due to the only thing that differs between them the program. Key to success of the experiment is random assignment of people into groups.