Flashcards in Experimental Research Deck (18)
Experimental research purpose
provide structure for evaluating cause-and-effect relationship between dependent and independent variables.
by degree of experimental control
True-experiment vs Quasi-experimental designs
by how subjects are assigned to groups
Between-subjects and Within-subjects designs
True experimental design
subjects randomly assigned to at least 2 comparison groups
does not meet requirements of true experiment
lacks random assignment, comparison groups, or both
used when true experimental design not feasible
accommodates for limitations in natural settings.
Between subjects design
subjects randomly assigned to independent groups
Within subjects design
subjects act as their own control
repeated measures design
Single factor design
structures the investigation of one independent variable
easy to develop
can't account for simultaneous interactions of several variables
incorporates two or more independent variables.
n-way design, a x b design, etc
Pretest-posttest control group design
basic structure of RCT
compares 2 or more groups that are formed by random assignment
changes from pretest to posttest that appear in experimental group but not control group:
can be reasonably attributed to the intervention
considered the scientific standard in clinical research for establishing cause-and-effect relationship
Pretest-Posttest Control Group Design
Posttest only control group design
identical to pretest-posttest but with no pretest administered to either group.
Used when pretest is impractical or reactive
Repeated measures design
ability to control potential influence of individual differences
uses subjects as their own control
potential for practice effects and carryover effects
When is a Repeated measures design used?
only used when outcome measure will revert back to baseline between interventions and pt problem will remain stable throughout study period
half of the subjects receive treatment A followed by treatment B. Other half B then A
subgroups randomly assigned into one of the sequences
When would you use a crossover design?
When patient's condition will not change over time
not a reasonable approach when treatment effects are slow
washout period is essential