Shit - Behavioural

Question 1

Measurement for case-control

Answer 1

OR = ad/bc

= have it and risk * not and don’t / have it and don’t * don’t have it but do

Question 2

Measurement for cohort

Answer 2

RR = (a/a+b)/ (c/c+d)

= risk of disease when you have exposure / risk of disease when you don’t have exposure

Question 3

Phases of clinical trials

Answer 3

I = safe (healthy ppl)
II = work - efficacy, AE, dose
III = good/better - common AE
IV = stay - rare/LT AE

Question 4

sensitivity =

Answer 4

= 1 - FN

Question 5

specificity =

Answer 5

= 1 - FP

Question 6

AR =

Answer 6

AR = (a/a+b) - (c/c+d)
= risk of disease when you have exposure - risk of disease when you don’t have exposure
= (RR - R unexposed)/RR

Question 7

RRR =

Answer 7

RRR = 1-RR

Question 8

ARR =

Answer 8

ARR = (c/c+d) - (a/a+b)

= risk of disease when you don’t have exposure - risk of disease when you have exposure

Question 9

NNT

Answer 9

NNT = 1/ARR

Question 10

NNH

Answer 10

NNH = 1/AR

Question 11

Precision

Answer 11

= reliability

decrease with random errors

Question 12

Accuracy

Answer 12

= validity

decrease with systematic errors

Question 13

Berkson bias vs. healthy worker bias

Answer 13

Berkson = study population from hospital is sicker than general population

HWB = study population is healthier than the general population

Question 14

lead-time vs latent period

Answer 14

lead time = find earlier so think it increases survival. Decrease effect with “back-end” survival measures

Latent period = time between intervention and effect. Measuring too soon could prevent you from seeing the result because it hasn’t happened yet

Question 15

SD %s

Answer 15

1SD = 68%
2SD = 95%
3DS = 99.7%

Question 16

Positive skew =

Answer 16

Tail on positive side; Mean > median

Question 17

Nevative skew =

Answer 17

Tail on negative side; Mean

Question 18

Power =

Answer 18

1-beta
= correctly rejecting the null

Increase power (decrease beta) via:

• increased “n”
• increased expected effect size
• increase precision of measurement

Question 19

Type I error

Answer 19

Falsely rejecting the null (FP error)

aka saw a difference when there is none

Question 20

Type II error

Answer 20

Failing to reject a false null (FN error)

aka didn’t see a difference when there really is one

Question 21

CI:

Answer 21

If CI includes there numbers, then fail to reject null:

Mean difference: 0
OR or RR: 1
Overlap between 2 groups’ CIs

Question 22

T-test

Answer 22

comparing 2 groups, numerical data

Question 23

ANOVA

Answer 23

Comparing ≥3 groups, numerical data

Question 24

Chi-squared

Answer 24

Comparing ≥2 groups, categorical data (i.e. ethnicity)

Question 25

Quarternary prevention

Answer 25

Identify patients at risk for unnecessary treatments

Question 26

Medicare vs medicaid

Answer 26

medicare = old, disabled, ESRD
Medicaid = very low income

Question 27

Parts of medicare:

Answer 27

A = hospital
B = basic clinic stuff
C = A+B via external company
D = drugs

Question 28

Therapeutic privilege

Answer 28

Withhold patient information if it will severely harm them or undermine their decision-making capacity
i.e. woman tells you she will kill herself if she has breast cancer because she watched her mom die from it you find a lump during exploratory surgery and take it out without permission

Question 29

Transfusion on minors of jahovas parents?

Answer 29

YES

Question 30

Power of attorney hierarchy

Answer 30

pt picks someone

pt can revoke this even if they are not competent

Question 31

Surrogate decision makers

Answer 31

spouse > adult child > parents > adult siblings > other relative

Question 32

APGAR

Answer 32

Appearance (colour)
Pulse (100)
Grimace (reflex to stimulus)
Activity (tone)
Respiration (quality)

Question 33

Object permanence age

Answer 33

9 months

Question 34

Positive likelihood ratio

Answer 34

sens/1-spec

Question 35

Negative likelihood ratio

Answer 35

1-sens/spec

Question 36

Parameters affected by disease prevalence

Answer 36

PPV and NPV

ex: higher prevalence = more TP = higher PPV
higher prevalence = less TN = lower NPV

Question 37

most resistant measure of central tendency to outliers

Answer 37

mode

Question 38

Least vs greatest financial risk methods of doctor reimbursement

Answer 38

Least risk = fee for service: get paid for every test, so order more tests

Highest risk = capitation: get paid a set amount per patient and insure the costs for tests, so more primary/secondary care to prevent diseases and catch them early to avoid expensive tests and surgeries

Question 39

Most preventable cause of disease and death in the USA

Answer 39

SMOKING!

Question 40

MCC cancer in women vs MCCD cancer in women

Answer 40

MCC = breast > lung > colon
MCCD = lung > breast > colon

Question 41

matching is used to decrease what type of bias:

Answer 41

confounding

Question 42

attrition bias is a type of what form of bias

Answer 42

Selection bias

(anything that causes a systematic difference between the groups terms of treatment response or prognosis

Question 43

Crossover study design:

Answer 43

case control where you switch the groups half way

Limitation = effect from one treatment carrying over. Limit this with a washout period

Question 44

Ecological study

Answer 44

Use populations, not people

Question 45

Power =

Answer 45

= the study’s ability to find a difference when one does exist
= 1-beta
(so beta = the probability of finding no difference when there is one i.e. failing to reject a false null)

Question 46

Hawthorne effect =

Answer 46

Participants altering their behaviour when they know they are being studied