Busy. Please wait.
or

show password
Forgot Password?

Don't have an account?  Sign up 
or

Username is available taken
show password

why


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
We do not share your email address with others. It is only used to allow you to reset your password. For details read our Privacy Policy and Terms of Service.


Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
Don't know
Know
remaining cards
Save
0:01
To flip the current card, click it or press the Spacebar key.  To move the current card to one of the three colored boxes, click on the box.  You may also press the UP ARROW key to move the card to the "Know" box, the DOWN ARROW key to move the card to the "Don't know" box, or the RIGHT ARROW key to move the card to the Remaining box.  You may also click on the card displayed in any of the three boxes to bring that card back to the center.

Pass complete!

"Know" box contains:
Time elapsed:
Retries:
restart all cards
share
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

USMLE 1

Stack #2728794

QuestionAnswer
Types of observational studies (5) Cross-sectional , case control, cohort , twin concordance and adoption.
Collects data from a group of people to asses frequency of disease at a particular point in time ( disease prevalence Cross-sectional study
Compares a group of people with disease to a group without disease (odds -ratio) Case-control study
Compares a group with a given exposure or risk factor to a group without such exposure (relative risk) Cohort study
Compares the frequency with which both monozygotic twins or dizygotic twins develop the same disease ( measures heritability and influence of environmental factors Twin concordance study
Compares siblings raised by biological vs adoptive parents Adoption study
Experimental study involving humans. Compares therapeutic benefits of 2 or more treatments, or of treatment and placebo Clinical trial
The sample consists on a small number of healthy volunteers (is it safe?) Phase 1 drug trials
The sample consists on a small number of patients with disease of interest ( does it work) Phase 2 drug trial
The study sample consists on a large number of patients randomly assigned either to the treatment under investigation or to the best available treatment ( or placebo)( is it as good or better?) Phase 3 drug trials
Is the post marketing surveillance of patients after treatment is approved Phase 4 drug trial
Proportion of all people with disease who test positive, or the probability that when the disease is present , the test is positive Sensitivity ( true positive rate )
Sensitivity formula SENS = TP/ ( TP + FN)
Proportion of all people without disease who test negative, or the probability that when the disease is absent, the test is negative Specificity ( true negative rate )
Specificity formula SPECIFICITY = TN / (TN +FP)
Proportion of positive test results that are true positive Positive predictive value
Positive predictive value formula PPV = TP / ( TP + FP)
Proportion of negative test results that are true negative Negative predictive value
Negative predictive value formula NPV = TN / ( TN + FN)
Created by: mune13