Quasi Experimental and single case experimental designs

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Quasi Experimental and
single case
experimental designs
Chapter 11
Program Evaluation
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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
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Types
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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
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Is the target population being reached?
Are the research questions being answered?
Program Evaluation
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Types
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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
Quasi experimental designs
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1 group posttest only design
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Has no comparison group
 Doesn’t have good internal validity
1 group pretest-posttest design
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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
Quasi experimental designs
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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.
Quasi experimental designs
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Nonequivalent control group design
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Nonequivalent control group pretest-posttest design
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Benefit: a pretest for comparison purposes
Interrupted time series design
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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
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Extension of the interrupted time series design with a control
group
Quasi experimental designs
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1 group posttest only design
 EXO
1 group pretest-posttest design
 EOXO
Nonequivalent control group design
 EXO
 C
O
Nonequivalent control group pretest-posttest design
 EOXO
 CO
O
Interrupted time series design
 EOOOXOOO
Control series design
E = experimental group
 EOOOXOOO
X = treatment
C = control group
 COOO
OOO
O = observation to collect data
Single case experimental
designs
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A.K.A. Single subject designs or Single participant
designs
Baseline control period  treatment period
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The change in behavior during these periods could be
attributed to a variety of things
Reversal designs
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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
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Multiple baseline designs
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Observing behavior before and after a
manipulation under multiple circumstances
Can be done
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Across subjects
Across behaviors
Across situations
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