Things I struggle with Flashcards
(925 cards)
case control study
copmapre a group of people with the disease to a group without the disease to look for risk factor. Odds ratio
cohort study
takes a group of people with a risk or exposure to a group without an exposure to see if it increases frequency of disease. Use relative risk
Phase 1 clinical trial
is it safe
phase 2 clinical trial
does it work
phase 3 clinical trial
is it better
phase 4 clinical trial
long term issues
sensitivity
a/a+c proportion of people with disease that test positive for disease. In other words, if the disease is present, the test will be positive. It is good for ruling out disease and indicates low false native. It is good for screening low prevalence disease
specificity
d/D+B- proportion of all people without disease who test negative. Disease is not present if the test is negative. It is good for confirming a positive screening test. It is used to rule in a disease
PPV
probation of positive test results that are true positive. If person tests +then they have disease. Prevalence increases the value
NPV
If person tests negative then they don’t have the disease. High prevalence means the NPV decreases.
incidence
number of new cases/ people at risk
prevalence
number of cases/people in population
chronic disease- changes in incidence and prevalence
prevalence is greater than incidence because there is a larger number of existing cases
when does the odds ratio equal the risk ratio
if the prevalence is low
precision
consistence and reproducibility of the test
accuracy
trueness of the test measurements
reliability
precision
validity
accuracy
Beckson Bias
hospital patients are used instead of normal healthy control
recall bias
can remember more exposures if there is a disease present
Pygmalian effect
observer believes the treatment works so records a biased view
Procedure bias
groups are not treated the same
confounding bias
other multiple factors are playing in
Hawthorne effect
people change behavior when being watched