Exam 1 Flashcards
Name examples of Experimental Studies
Controlled, Uncontrolled, Single/double blinded, Randomization, self controls, external controls
What is a Case-Series?
Researcher rep[orts on certain characteristics within a group, or series, of patients and describes in published report.
usu short time span, no control subjects by definition,
not planned in advance, no hypothesis.
PLAY IMPORTANT ROLE AS PRECURSOR TO OTHER STUDIES
What is a Case-Control Study?
Retrospective (backward-looking) over an extended period of time. Goes from outcome –> risk factors, tries to find out why.
Has a control group.
Begins with presence/absence of an outcome and then looks back to try to detect possible causes (maybe suggested in case-series report?)
What is a Cross-Sectional study?
a survey.
analyses data collected on a group of subjects at one time.
aka- prevalence studies
What is a Cohort Study?
Prospective (forward looking) ask, “what will happen?” sets up the rules first.
usu. long term, participants may be seen many times.
The “cadillac” of observational research.
Have the ability to examine the causes of disease. (but not as strong as an experimental study) ex: effects of smoking
What is a control?
group of people not receiving the thing (treatment, meds, etc) being investigated. Gives a basis for comparison.
What are trials with Independent Concurrent Controls?
studies with a control group that is receiving no treatment during the same time period as the experimental group
What is blinding? Single blind? Double blind?
when someone involved in research doesn’t know what is the control vs. the experimental.
Single blind- participant doesn’t know which group they are in but researcher does
Double blind- subject and researcher are both unaware of which group the subject is in.
What return rate does a cross-sectional study need for validity?
33%
Can observational studies determine causation?
No, only associations
Why is case-control not as strong a study as cohort?
because in looking backward to determine causation, information may be missed
What is a positive correlation?
as one factor increases, so does a second factor
ex: the older one gets, the more likely to die
Positive correlation= 1.0 upward slanting from left to right
What is a negative correlation?q
as one factor increases the other factor decreases
ex: with increasing age, mobility decreases
denoted as -1.0, downward sloping line from left to right
What is a correlation of zero?
Two factors show no statistical relationship, dots are all over, don’t make a line.
No association
What is randomization?
having a random assortment of traits of subjects in both control and experimental groups.
ex: not have all women in one group and all men in the other
