Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.
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Transcript of Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.
![Page 1: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/1.jpg)
Quasi-Experimental Designs
Slides Prepared by Alison L. O’Malley
Passer Chapter 11
![Page 2: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/2.jpg)
Quasi-Experimentation
•Quasi-experiments resemble experiments, but lack experimental control
•Generally, lack of random assignment is the key point of distinction between quasi-experiments and “true” experiments (Shadish, Cook, & Campbell, 2002)
•Quasi-experiments are thus more vulnerable to internal validity threats
If quasi-experiments lack experimental control, what good are they?
![Page 3: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/3.jpg)
Quasi-Experimentation:Designs without a control group
•One-group posttest-only design•A treatment occurs and the DV is measured
afterward
What threats to interval validity are present here?
![Page 4: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/4.jpg)
Quasi-Experimentation:Designs without a control group •One-group pretest-posttest design •DV measured before and after treatment
![Page 5: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/5.jpg)
Quasi-Experimentation:Designs without a control group •Simple interrupted time-series design •DV repeatedly measured before and after a
treatment •History is the primary threat to internal
validity
![Page 6: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/6.jpg)
Quasi-Experimentation:Designs with a nonequivalent control group
• Selection emerges as a major threat to internal validity
• Selection may interact with other threats (i.e., selection interactions)
• In such cases, the threat is labeled by replacing the term “selection” with “differential” (e.g., differential attrition, differential testing)
![Page 7: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/7.jpg)
Quasi-Experimentation:Posttest only with nonequivalent control group
•Participants in one condition exposed to a treatment•Participants in the other nonequivalent condition are not exposed to the treatment •Outcome measures obtained from both groups •Lack of pretests poses difficulties in interpreting results
![Page 8: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/8.jpg)
Quasi-Experimentation:Pretest-posttest with nonequivalent control group
•Pretreatment and posttreatment scores are obtained for a treatment group and a nonequivalent control group
•What benefits are added by this research approach?
![Page 9: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/9.jpg)
Quasi-Experimentation:Simple interrupted time-series with nonequivalent control group
•A series of pre- and posttreatment scores are obtained for a treatment group and a nonequivalent control group
![Page 10: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/10.jpg)
Quasi-Experimentation:Simple interrupted time-series with nonequivalent control group
•What information can be obtained from examining the pretreatment trend lines?
![Page 11: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/11.jpg)
Switching Replication Designs
•One group receives a treatment while a nonequivalent group does not receive a treatment but is then exposed to treatment down the road •Can be used with both pretest-posttest and time-
series designs • In the switching replication with treatment
removal, the initial treatment group no longer receives the treatment once the control group is switched
![Page 12: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/12.jpg)
Switching Replication with Treatment Removal
How might you improve the design of this study?
![Page 13: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/13.jpg)
Program Evaluation
• Assesses the need for as well as the design, implementation, and effectiveness of a social intervention
• What is a recent social intervention undertaken in your community?
![Page 14: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/14.jpg)
Program Evaluation
• Much talk surrounds “evidence-based” programs and public policies
• How do you know whether a program or policy works?
![Page 15: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/15.jpg)
Program Evaluation: Needs Assessment
• Needs assessment determines whether there is a need for a social program, and if so, what is required to meet the need
• Must acquire data from a wide range of sources
![Page 16: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/16.jpg)
Program Evaluation: Program Theory and Design Assessment
• Rationale for designing a program in a particular way – theoretical and empirical justification
![Page 17: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/17.jpg)
Program Evaluation: Process Evaluation
• Is program implemented as intended? • Also known as program monitoring
![Page 18: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/18.jpg)
Program Evaluation: Outcome Evaluation
• Likely more comfortable terrain, as this deals with assessing program (treatment) effectiveness
• If randomized controlled trials aren’t possible, turn to alternative designs
![Page 19: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/19.jpg)
Program Evaluation: Outcome Evaluation
• Watch out for contamination, which occurs when knowledge, services, or other experiences intended for one group are unintentionally received by another group
![Page 20: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/20.jpg)
Program Evaluation: Efficiency Assessment
• Cost-benefit analysis of program effectiveness
• Is the program financially beneficial?
![Page 21: Quasi-Experimental Designs Slides Prepared by Alison L. O’Malley Passer Chapter 11.](https://reader036.fdocuments.in/reader036/viewer/2022062500/5697bfa71a28abf838c98b34/html5/thumbnails/21.jpg)
Program Evaluation: Program Diffusion
• Implementing and maintaining effective programs in other settings or with other groups
Dissemination Adoption Implementation Sustainability