RESEARCH METHODS

• R Random Assignment
• X Intervention(s) (Subscripts indicating different interventions)
• O Observation (pretest or posttest)
• A,B,C,D Groups of subjects

• Often called Pre-experimental
• - usually have inadequate control of extraneous variables
• - GROUP (A) --> Intervention (X) --> Posttest (O)

• Group (A)--> Pretest(O)-->Intervention(X)-->Posttest(O)
• - possible affects from extraneous events
• - Regression is possible
• - pretest can affect attitudes
• - Attrition can be a problem
• - Maturation is a potential threat

Has a comparison or control group, but no pre-test. One group receives the treatment, while the other group (B) acts as a control, receiving no treatment.

• Group (A)--> Intervention (X)--> Posttest (O)
• Group (B)--------------------------> Posttest (O)

• In some, groups recieve different treatments:
• A--> X1-->O
• B--> X2-->O
• C--> X3-->O

Where one group will get pre and post test with Intervention. The other group will also get pre and post test, but with no Intervention, or different interventions.

• A--> O--> X--> O
• B--> O--------->O

or

• A--> O--> X1--> O
• B--> O--> X2--> O
• C--> O--> X3--> O