The posttest-only control group design is a research design in which there are at least two groups , one of which does not receive a treatment or intervention, and data are collected on the outcome measure after the treatment or intervention.
What is the difference between a posttest-only design and a pretest posttest design?
Pretest–posttest designs are employed in both experimental and quasi-experimental research and can be used with or without control groups. For example, quasi-experimental pretest–posttest designs may or may not include control groups, whereas experimental pretest–posttest designs must include control groups.
What is a posttest design?
A type of true experimental design where test units are randomly allocated to an experimental group and a control group . The experimental group is exposed to a treatment and both groups are measured afterwards.
What are two advantages to a posttest-only design?
The key threats to this design are history and maturation. When might you use the posttest-only design? The advantage would be that without a pretest you wouldn’t be taking as much time . The disadvantage would be the useful-side of the pretest where you can see changes as well as attrition effects.
What is a one group posttest design?
A one-group pretest–posttest design is a type of research design that is most often utilized by behavioral researchers to determine the effect of a treatment or intervention on a given sample . ... The first feature is the use of a single group of participants (i.e., a one-group design).
What are the advantages of posttest-only design?
When might you use the posttest-only design? The advantage would be that without a pretest you wouldn’t be taking as much time . The disadvantage would be the useful-side of the pretest where you can see changes as well as attrition effects.
What is the difference between pretest and posttest?
Typically, a pretest is given to students at the beginning of a course to determine their initial understanding of the measures stated in the learning objectives, and posttest is conducted just after completion of the course to determine what the students have learned.
What’s the main downside of a pretest posttest design?
The only disadvantage of the pretest-posttest control group design compared to the posttest only design, is that there can be a threat to internal validity called the testing threat . As was discussed in an earlier chapter, this threat can occur when there is an interaction between the pretest and the treatment.
How do you identify a quasi-experimental design?
Like a true experiment, a quasi-experimental design aims to establish a cause-and-effect relationship between an independent and dependent variable. However, unlike a true experiment, a quasi-experiment does not rely on random assignment. Instead, subjects are assigned to groups based on non-random criteria .
Is quasi-experimental qualitative or quantitative?
Quasi experiments resemble quantitative and qualitative experiments , but lack random allocation of groups or proper controls, so firm statistical analysis can be very difficult.
What is a one shot case study design?
A type of pre-experimental design where a single group of test units is exposed to an experimental treatment and a single measurement is taken afterwards . It only measures the post-test results and does not use a control group.
What is the main advantage of the randomized matched subjects posttest-only control group design?
Because no data are collected before the administration of the treatment or intervention (i.e., no pretest), the posttest-only control group design requires fewer resources (e.g., time, money, energy) for data collection . In fact, collecting data prior to a treatment or intervention may not be possible or feasible.
What are the limitations of experimental designs?
Limitation: They may be more expensive and time consuming than lab experiments . Limitation: There is no control over extraneous variables that might bias the results. This makes it difficult for another researcher to replicate the study in exactly the same way.
What are the limitations of one group posttest design?
Limitation due to maturation :
So since certain factors are essentially hard to predict and since 1 measurement is certainly not enough to understand the natural pattern of an outcome, therefore with the one-group posttest-only design, we can hardly infer any causal relationship between intervention and outcome.
What is two group design?
A two-group design is when a researcher divides his or her subjects into two groups and then compares the results . The two groups usually consist of a control group, who does not get the treatment, and a treatment or experimental group, who does get the treatment.
What is a mixed factorial design?
A mixed factorial design involves two or more independent variables , of which at least one is a within-subjects (repeated measures) factor and at least one is a between-groups factor. In the simplest case, there will be one between-groups factor and one within-subjects factor.
