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Flashcards in Behavioral Science - UWorld Deck (18)
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A payer pays a fixed predetermined fee for all healthcare services required by a patient

Capitation. This is the concept behind HMOs.


Positively vs. negatively skewed Bell curve

Positively skewed = most scores are on the lower end and mean > median > mode

Negatively skewed = most scores are on the high end and mode > median > mean


Attrition bias

Study subjects are assigned to groups in a non-random fashion


Cancers with highest incidence/mortality in US men and women

Men incidence: prostate > lung > colon
Men mortality: lung > prostate > colon

Women incidence: breast > lung > colon
Women mortality: lung > breast > colon


Study's ability to detect a difference when one exists

Power = 1 - beta, where beta = the likelihood of making a type II error (accepting the null when it's actually false...i.e. say there isn't a difference when there truly is). Thus, power is the likelihood of rejecting the null when there really is a difference.


Type I error

Reject the null when it's actually true...i.e. say there is a difference when there's truly not.


Odds ratio

AD/BC. Only use in case-control studies because you do not follow patients over time and cannot assess risk.


A new study is developed for prostate cancer that is negative in 95% of patients who do not have cancer. If the test is used on 8 blood samples from patients without prostate cancer, what is the probability of getting one false-positive result?

The probability that one sample tests positive = 1 - (0.95^8) because you are testing the probability of a series of independent events, which requires mulitplication of the probability of each individual event.


Relative risk

[a/(a+b)] / [c/(c+d)]


How do you relate carrier, disease and gene frequency for an autosomal recessive disease with only two possible alleles?

Hardy-Weinberg Principle: p^2 + 2pq + q^2 = 1

-p = homozygous dominant individuals
-2pq = carrier frequency
-q = homozygous recessive individuals (q^2 = disease frequency for autosomal recessive diseases)

***It is important to remember that you only need one value, p or q, and then you can calculate the frequency because there are only two alleles for the disease. Plug your known value into the Hardy-Weinberg equation, then substitute that value for (p+q)=1 and solve for the other variable, then plug it back into the Hardy-Weinberg Principle and it will give you that genotype frequency in the general population.


Absolute risk reduction

Event rate in control group - Event rate in treatment group


Relative risk reduction

Absolute relative risk / control rate.


Number needed to treat

1/Absolute risk reduction or 1/(control rate - treatment rate)


When does the OR approach RR?

When disease incidence is low


Number needed to harm

1/Attributable Risk (treatment group event rate - control group event rate)


Benzo with short t1/2 that can be used for short-term insomnia treatment in patients that cannot tolerate daytime sleepiness



Attributable risk percent

100 x [(exposed risk) - (unexposed risk)]/exposed risk

or more simply

100 x (RR - 1)/RR


Hypomanic vs. manic

Hypomanic = no psychosis, less severe, preserved functional status

Manic = more severe, > 1 week with functional impairment