Research Flashcards
Independent variable
intervention or condition
-Cause or influences the dependent variable.
Controlled and manipulated by the researcher
Dependent variable
outcome or response
Clinical trial
research design tests how well methods of screening, preventions, diagnosis, or tx of dx work in people
Completely randomized design
random assignment to group with unique intervention
outcomes btwn groups compared at end of trial.
- parallel design
cross over design
subject is the own control
subject gets both treatments
Factorial design
subjects experience different combination of 2 more interventions
- subjects get different combos of levels of ind variable
Pretest-posttest design control group design
- basic format of randomized controlled trial
- testing of randomized groups before and after treatment
posttest only design control group design
randomized groups are only tested after the intervention
repeated measures design
subjects acts as own control
subjects are tested under all conidtions
also known as within subjects design
Sequential clinical trial
Data is analyzed as it becomes available so trial can be stopped as soon as evidence is sufficient enough to show difference between treatments
Single subject design
Conclusions can be drawn from the effects of a treatment based on single patient.
-Uses repeated measurments overtime for at least two periods/pieces.
- Baseline (A) equal prior to treatment
- Intervention phase (B) after treatment
- intervention phases replicated to create design
(A-B) (A-B-A)(B-A-B)
Quasi experimental design
Research design without control group, random assignment, or both
- One group pretest post test design.
- One way repeated measures design overtime.
- Time series design.
One group pretest post test design ; Quasi experimental design
Measurements on 1 group of subjects before and after treatment.
Time = independent variable with two levels (pretest and post test)
One way repeated measures design overtime; Quasi experimental design
Measurements on 1 group made at prescribed time intervals.
Time series design;Quasi experimental design
multiple measurements made before and after treatment observed patterns or trends during pre-treatment and post treatment periods
Internal validity
Intervention causes the outcome.
- Control of extraneous variables and sources of bias that may reduce validity of results
- blinding
- control groups establishment
- Matching/ pairing
- Intent to treat analysis
what is blinding and what different types exist in order to create internal validity
Method to keep individuals knowing from which subjects have received intervention or not. Reduce bias and placebo effect
Single blind: subjects are unknowing of group assignment until end of study
Double blind:Subjects and some researchers unaware of hypothesis or group assignment until end of study
Triple blind: Subject, members of research team, and data analyzers unaware of research hypothesis group assignment until end of study
Control group; what are the two most common forms of control?
- Statistically identical to treatment group, except for variable of interest.
- Help isolate the effects of the independent variable
- Active control: Effective (not sham) treatment is compared to experimental treatment. When effective treatment is available it is unethical to use placebo controlled for comparison to experimental treatment.
- Placebo control:Active substance/treatment that looks the same and is administered the same as the active drug or treatment
What is Matching/ pairing used for ? What is it?
- Method to increase internal validity
- Before random group assignment subjects who have a identical characteristics (weight age and race) are selected in order to ensure result in groups are based on important variables that may affect outcome
What is intention to treat analysis, why is it used
All subjects are analyzed together.
This preserves original balance of subject groups through randomization.
