Study Designs Flashcards
? Studies: researcher does not intervene or manipulate conditions; just gather information
Observational Studies
? Studies: results are measures of association and correlation, not causation
Observational Studies
? studies: researcher does no manipulation, just collect data, “watch and wait” for outcomes. Outcome is measured after exposure
Prospective studies
? Studies: outcome is measured before the exposure (can be from non-research data)
Retrospective studies
Observational studies include:
- Cross-sectional studies
- Case-control studies
- Cohort studies
? studies: measure expose and outcome simultaneously
Cross-sectional studies
NHANES and BRFSS are examples of
Cross-sectional studies (exposure and outcome measured at the same time)
? studies efficient when starting to explore as issue
cross-sectional studies
? studies: measure outcome at start of study and go backwards to measure exposure
case-control studies
advantage of ? study is you can look at multiple exposures which is efficient for rare conditions. subject to recall bias since it’s based on memory
case-control studies
? study: exposure it measured before the outcome develops.
Cohort studies
_____ can be prospective or retrospective
Cohort studies
? studies: (+) standardized measurement, cheaper than randomized trial
(-) lack of randomization, can be very long
cohort studies
—– variable affects the ——variable
independent (x), dependent (y)
_____: is what you manipulate
_____: is what you measure
Independent
Dependent
? studies: researches manipulate the environment.
Experimental studies
_____ are randamized controlled trials
Experimental studies
All randomized controlled trials are____
prospective
Other factors and circumstances
confounders
Recipients feel like they are getting an intervention, believe in it, and show improved outcomes
Placebo
If a study is randomized, one can infer____ and not ___ or____
causation, not correlation or association
____ refers to a statistical parameter often called r. you can measure quantitatively but only for linear relationship
Correlation
Positive Correlation
X and Y increase or decrease together
Negative Correlation
as X increases Y decreases, or as X decrease, Y increases
Correlation coefficient r can range from
-1 to +1
A perfect positive correlation is ___ and a perfect negative correlation is ____
+1, _1.
A stronger correlation is going to be an r closer to ___ or ____ such as _____
+1 and -1 such as +0.80 and -0.80
