Quasi Experimental and single case experimental designs Chapter

Quasi Experimental and single case experimental designs Chapter 11

Program Evaluation l l l 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

Program Evaluation l Types l l l Needs assessment l What problems, if any, need to be addressed? l Once identified researchers can plan accordingly Assessment of program theory l Used to fix problems found in a needs assessment l Involves collaboration of service providers, researchers, clientele, etc… Process evaluation l 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?

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

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

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

Quasi experimental designs l Nonequivalent control group design l l l Nonequivalent control group pretest-posttest design l l Benefit: a pretest for comparison purposes Interrupted time series design l l l A separate control group Selection differences – choosing groups based on naturally existing categories; this is why study is called nonequivalent 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 l Extension of the interrupted time series design with a control group

Quasi experimental designs l l l 1 group posttest only design l EXO 1 group pretest-posttest design l EOXO Nonequivalent control group design l EXO l C O Nonequivalent control group pretest-posttest design l EOXO l CO O Interrupted time series design l EOOOXOOO Control series design E = experimental group l EOOOXOOO X = treatment C = control group l COOO O = observation to collect data

Single case experimental designs l l A. K. A. Single subject designs or Single participant designs Baseline control period treatment period l l The change in behavior during these periods could be attributed to a variety of things Reversal designs l l 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

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