Lecture 5 - Study Design

Question 1

in the hierarchy of evidence, meta-analysis/systematic review is at the _____ and case series/case reports are are at the _____

Answer 1

top;

bottom

Question 2

2 types of studies:
______ describe the general characteristics of the distribution of a disease;
_____ test hypotheses or provide explanations about a disease/phenomenon

Answer 2

descriptive (ie case report, case series);

analytic (ie case control, cohort)

Question 3

in a _____ study, the frequency of a disease and frequency of risk related factors are assessed in the present. one problem is it does not establish _____

Answer 3

cross sectional;

causality (ie only association)

Question 4

cross sectional studies look at disease _____.

Answer 4

prevalence

Question 5

a ____ ____ describes the presentation of a disease in one patient. a ____ ____ describes the presentation of a disease in a number of patients

Answer 5

case report;

case series

Question 6

experimental designs:
____ subjects = comparing subjects in 1 group to subjects in another group;

______ design = subjects recieve sequence of 2 or more treatments given consecutively, usually with a washout period

_____ subjects = comparisons are being made within the same subject

Answer 6

between;
crossover;
within

Question 7

_____ studies compare a group with a given exposure to a group w/o such exposure

Answer 7

cohort

follow patients for development of disease

Question 8

cohort studies can be _____ ie “who will develop the disease” or ______ ie “who developed the disease”

Answer 8

prospective;

retrospective

Question 9

what measure do you use with cohort studies?

Answer 9

relative risk

Question 10

relative risk:

risk of developing disease in the ____ Group divided by risk in the ____ group

Answer 10

exposed;

control (unexposed)

Question 11

when relative risk = ____, there is no association between exposure and the disease

Answer 11

1

Question 12

RR > 1 = exposure is associated with ____ disease occurrence;

RR < 1 = exposure is associated with _____ disease occurance

Answer 12

increased;

decreased

Question 13

_____ studies compare a group of people with disease to a group without the disease

Answer 13

case-control

looks in past for history of exposure

Question 14

what measure do you use with case control studies?

Answer 14

odds ratio

Question 15

what bias can occur with case-control studies?

Answer 15

recall bias

Question 16

odd’s ratio:

depicts the odds of an event occurring _____ an exposure vs the odds of an event occurring _____ an exposure

Answer 16

with;

without

Question 17

equation for odd’s ratio (using 2x2 table):

Answer 17

ad/bc

ie odds even occurred with exposure / odds event occurred without exposure

Question 18

case control studies start with the ____ as the study group; then find ____ groups

Answer 18

outcome;

control

Question 19

for a OR or RR to be significant, the 95% confidence interval should not include ____

Answer 19

1