11: Quasi Experimental Designs and Applied Research

Question 1

What are some design problems in applied research

Answer 1

Ethical dilemmas

lowered internal validity

cant use random assignment to form equivalent groups - between

uncontrolled sequence effects -within

Question 2

What are examples of quasi-experimental designs

Answer 2

• If subjects cannot be assigned randomly
• Single-factor ex post facto designs, two or more levels
• Ex post facto factorial designs
• P x E factorial designs
• All of the correlational research

Question 3

Explain the purpose of non-equivalent control group designs

Answer 3

to evaluate the effectiveness of some treatment program - those in the program are compared to a control that are not treated

Question 4

Explain what a non-equivalent control group design is

Answer 4

The groups are not equal at the start of the study; in addition, they experience different events in the study itself
Statistical comparison is typically between the change scores (difference in pretest and post-test)

Question 5

Explain what an interrupted time series design is

Answer 5

Data is collected consistently for an extended period before and after the event expected to influence behaviour
the outcome is that it evaluates trends

Question 5

what are the three approaches to interrupted time series design

Answer 5

add a control group

interrupted time series design with switching replications: When a program can be introduced in different locations at different times

measure several dependent variables, some expected to be influenced by the interruption and others not expected to change.