Experimental Design Flashcards
Negative Control
Group added where you know the outcome but the IV will not affect the group
- Often considered the best control
- Helps guard against epiphenomenon (result that accompanies another, but has no causal influence itself or what not caused by the experiment) – an observed effect in this control means there’s something else influencing the DV.
- Known to give a - result.
Positive Control
Group added to a design where you know what the outcome will be, and the outcome is expected to move in the direction you think the IV should move it
- Used to ensure the experimental set up is working
- Provides comfort about the effects of the IV
- Similar to the actual experimental test, but which is known to give a + result
Vehicle Control
Injectate or pill without the substance (placebo) Contains everything you are administering except the level of IV
Sham Control
Generally associated with a surgical procedure, in while a mock surgery is performed. Form of procedural control.
Procedural control
Running the same procedure without the active intervention.
*One group has one procedure, other group has slightly altered procedure w/o the IV
Repeated measures
Use the subject as their own control, or alternatively using one side of the animal as a control for another animal
*This method can sometimes introduce possible learning curves/practice effect
Hypothesis driven
Research in which a specific hypothesis is laid out upfront and then tested prospectively
Prospective study
Hypothesis laid out and research is analyzed based off data obtained in the future, after application of the IV.
Retrospective studies
Assess effect of an IV after the fact.
Discovery research
formulates the basis for hypothesis driven research
*Generates Ho
Clinical Trial
study of a group of individuals that have something is common and who are assessed as they move forward in time (Prospective study)
**Usually assessed more than once (Repeated measure).
Clinical Trial
A study on patients (human) that is prospective, and tests a very SPECIFIC question- generally about a drug or specific intervention.
*Is the most rigorous (from control perspective)
Cohort study
study of a group of individuals that share something in common, and who are assessed as they move forward in time (prospective)
- Greater work load
- Over a time period
- Usually repeated measure.
Cross-sectional study
Similar to a cohort study, except that all the measures are taken at the same time (one point in time, usually present) “snap-shot” of your test population at specific time point.
- Retrospective study
- Prevalence study
Case-control study
Similar to cross-sectional study, except that these are looking at various past times– identifies one group with variable, one without said variable, and assesses their PAST habits/lifestyles in order to formulate an association.
- Retrospective
- Past focused
Ethnographic research
Study of human behavior in natural context, involving OBSERVATION of behavior in physical setting
Explanatory Research
Where the experimenter seeks to determine cause and effect. NOT and association.
*Most studies look at associations between IV and DV, not cause and effect
Historical Research
The systematic collection and evaluation of data relation to past occurrences in order to describe causes, effects, and trends of those events that may help explain present events and anticipate future events
Quasi-experiment
*Empirical study
used to estimate the causal impact of an intervention on a target population.
*Share many elements with traditional experimental design, but lack the element of random assignment to control or treatment
*The investigator does not have control over the assignment of the IV as true in other experimental design – but is not random, some control through other methods (ie, eligability cut-off)
Prevention Trials
Look for better ways to prevent disease in people who do not have the disease
*Outcome research
Screening Trials
Test the best way to detect a certain disease of condition,
Diagnostic Trial
Conducted to find better tests or procedures for diagnosing a particular disease/condition
Increases diagnostic value
Treatment Trial
tests experimental treatments, new combinations of drugs, or new approaches to surgery/radiation therapy
Quality of Life Trials
(Supportive Care trial) Explores ways to improve comfort and quality of life for individuals with chronic/terminal illness