Quasi Experimental and single case experimental designs

1. Quasi Experimental and single case experimental designs Chapter 11

2. Program Evaluation • Research on programs that are proposed and implemented to achieve some positive effect on a group of people • i.e. DARE program evaluation • Applies research approaches to evaluate types of programs

3. Program Evaluation • Types • Needs assessment • What problems, if any, need to be addressed? • Once identified researchers can plan accordingly • Assessment of program theory • Used to fix problems found in a needs assessment • Involves collaboration of service providers, researchers, clientele, etc… • Process evaluation • Program monitoring to determine if program is doing what it is supposed to • Is the target population being reached? • Are the research questions being answered?

4. Program Evaluation • Types • Outcome evaluation • Impact assessment • What did the participants like/dislike about the study? • Studying the outcome and then assess the impact of the outcome measure. • Efficiency assessment • Was the program worth it? • Did the benefits outweigh the costs? • Uses quasi-experimental designs to assess effectiveness and efficiency

5. Quasi experimental designs • 1 group posttest only design • Has no comparison group • Doesn’t have good internal validity • 1 group pretest-posttest design • History • Could confound results • Maturation • People change over time and this could skew results • Testing • Previous experience could change behavior • Instrument decay • the deterioration of research instruments or methods during a study

6. Quasi experimental designs • Instrument decay • equipment may wear out, respondents may become more casual in recording their responses. • Regression toward the mean • a.k.a statistical regression • The tendency for extreme scores in a distribution to move (regress) toward the mean of the distribution w/ repeated testing. • Problem of reliability • Occurs when a set of extreme scores collected at one time point is compared to scores taken at another time point.

7. Quasi experimental designs • Nonequivalent control group design • A separate control group • Selection differences – choosing groups based on naturally existing categories; this is why study is called nonequivalent • Nonequivalent control group pretest-posttest design • Benefit: a pretest for comparison purposes • Interrupted time series design • Measurement of dependent variable is interrupted by the quasi independent variable • By taking multiple measurements you can look at the effectiveness of a treatment before and after it is introduced. • Control series design • Extension of the interrupted time series design with a control group

8. Quasi experimental designs • 1 group posttest only design • E X O • 1 group pretest-posttest design • E O X O • Nonequivalent control group design • E X O • C O • Nonequivalent control group pretest-posttest design • E O X O • C O O • Interrupted time series design • E O O O X O O O • Control series design • E O O O X O O O • C O O O O O O E = experimental group X = treatment C = control group O = observation to collect data

9. Single case experimental designs • A.K.A. Single subject designs or Single participant designs • Baseline control period  treatment period • The change in behavior during these periods could be attributed to a variety of things • Reversal designs • To determine if treatment had an effect, revert back to baseline (no treatment) and look at the differences • ABA design • Baseline control period  treatment period  control period • Can also do a ABAB design

10. Single case experimental designs • Multiple baseline designs • Observing behavior before and after a manipulation under multiple circumstances • Can be done • Across subjects • Across behaviors • Across situations