Experimental Design Flashcards
What is a clinical trial?
a type of research design that tests how well methods of screening, prevention, diagnosis or treatment of a disease work in people
What is a completely randomized research design?
subjects are randomly assigned to different groups and each group receives a unique intervention and the outcomes are compared at the end of the trial
a.k.a parallel groups design
What is a crossover design?
subject receives both interventions in random order separated by a period of no treatment
each subject serves as their own control
What is a factorial design?
two or more independent variables are investigated with different subjects assigned to the various combinations of levels of the independent variables
What is a pre-test/post-test control group design?
compares the outcomes of two or more groups formed by random assignment
basic format of a randomized control trial
What is a posttest only control group design?
compares the outcomes of two or more groups only after the treatment
What is a repeated measure design?
subjects are tested under all conditions and therefore each person acts as their own control
within subjects design
What is a sequential clinical trial?
data is analyzed as it becomes available so the trial can be stopped as soon as the evidence is sufficient to show a significant difference between treatments
What is a single subject design?
permits drawing conclusions about the effects of treatment based on the response of a single patient
What is a quasi-experimental design?
a type of research design without a control group,
random assignment of subjects to group, or both
What is the difference between single blind, double blind, and triple blind studies?
Single- subjects are unaware of the research hypothesis and the group to which they were assigned until the end of the study
Double: subject and certain members of the research team are unaware of the research hypothesis and the group to which each subject was assigned until the end of the study
Triple: subject, some team members, and data analyzers are unaware of the research hypothesis and the group to which each subject was assigned until the end of the study
What are the two main types of control groups?
Active Control-using a proven effective treatment as control to compare the effects of the study intervention
Placebo- inactive treatment that looks similar to the actual experimental intervention
What is an intention-to-treat analysis?
method of analysis in which all subjects in one of the treatment groups is analyzed together regardless if the received or completed that treatment to preserve the original balance of subject groups achieved through randomization
What is the difference between internal and external validity?
What are some threats to each?
External-degree in which results of a study can be generalized to the population outside of the trial group
Internal- degree in which the intervention being evaluated is the cause of the outcome measured and not the result of extraneous factors
What is the Hawthorne Effect?
an untreated subject experiences a change simply from participating in a research study and the tendency for individuals to change their behavior in response to the fact they are being observed or studied
