Lecture 4 - Observational studies

Question 1

Observational studies have high ___ validity

Answer 1

external

Question 2

What are the pros of that overlap btw case reports and case series

Answer 2

new disease to attention, high lights unusual findings, discovers new side effects and mutations

Question 3

which observational study plays a role in human tetralogy?

Answer 3

case reports and series

Question 4

what are the pros of case series

Answer 4

characterize rare diseases

Question 5

What are the cons of case reports

Answer 5

not generalizable, not based on systemic studies, associations may have other explanations

Question 6

what are the cons of case series

Answer 6

subject to selection bias, no control, not generalizable

Question 7

what are the cons of retrospective

Answer 7

relies on availability and accuracy of data records

Question 8

for cases, ______ cases are preferred to ______ cases

Answer 8

incident cases are preferred to prevalent cases

Question 9

What are the pros of case control study

Answer 9

useful for studying multiple exposure factors and rare diseases, inexpensive

Question 10

what are the cons of case control study

Answer 10

cant estimate incident or exposure rate, difficult to estimate temporality

Question 11

what is temporality

Answer 11

did exposure come before disease or vice versa?

Question 12

define one to many matching

Answer 12

Matching multiple controls to each case.

Question 13

define group matching

Answer 13

select controls based on the proportion of a characteristic in the cases

Question 14

what are the pros of matched case control

Answer 14

removes risk factors (confounders) that may not be evenly distributed

Question 15

what are the cons of matched case control

Answer 15

inefficient, hard to find controls, overmatching, cant study matched variables

Question 16

Define over matching

Answer 16

matching on variables that arent of interest

Question 17

Define odds

Answer 17

probability an event will occur/probability an event wont occur

Question 18

Define odds ratio

Answer 18

odds of a case being exposed compared to odds of a control being exposed

Question 19

interpret an odds ratio

Answer 19

the odds of getting a disease if you did the exposure was ___x that of someone who didnt do exposure

Question 20

OR>1

Answer 20

positive association, therefore harmful

Question 21

OR<1

Answer 21

negative association, therefore protective

Question 22

Matched pairs can be ____ or ___-

Answer 22

concordant or discordant

Question 23

define concordant

Answer 23

both case and control are exposed or unexposed

Question 24

define discordant

Answer 24

either case/control is exposed and the other isnt

Question 25

the 2x2 table of matched pair odds ratio emphasized what?

Answer 25

exposure

Question 26

Matched pair odds ratio only determines ratio of

Answer 26

discordant pairs

Question 27

What is the equation for odds ratio matched pair?

Answer 27

case exposed:controls not exposed / case not exposed:controls exposed