Study Design/Internal Validity

PUBH 6235

Week 8: Study Design/Internal Validity

Please respond to the following questions either by writing the design name or by describing the design using standard notation (X = program, O=observation, R= random assignment). For each design, please discuss all threats to internal validity.

1. a. Design: Single group post-test only

b. Internal validity threats:

1. a. Design: (R) O1 X O2

   (R) O1 O2

    

   b. Internal validity threats:

    

    

2. a. Design: Pretest-posttest design with experimental and comparison group

    

   b. Internal validity threats:

    

    

   4. a. Design: O X O

    

   b. Internal validity threats:

    

    

   5. a. Design: Single group with three pretests and four posttests

    

   b. Internal validity threats: