Study Design (Segars)

Question 1

In interventional study designs, list in order of increasing evidence:

Answer 1

Phase 0 –> Phase 1 –> Phase 2 –> Phase 3 –> Phase 4

Question 2

In observational study designs, list order of increasing evidence:

Answer 2

Cross sectional –> Case control –> Cohort

Question 3

__=outcome is NOT yet known at start of study

__=outcome IS already known at the start of the study

Answer 3

prospective

retrospective

if don’t know the outcome at the beginning, its a prospective study

Question 4

which studies prospective only?

Answer 4

Phase 0-4 (interventional)

Cohort (Observational)

Question 5

Is researcher forcing group allocation?
Yes=__
No=__

Answer 5

Yes –> Interventional (Buzz word=Randomization) (sample size/focus/duration)

No –> Observational (outcome/exposure)

Question 6

If you see “randomization” in a question stem, its what study design?

Answer 6

Interventional

Question 7

For observational studies, if groups organized by DISEASE STATUS, it is a __ study

Answer 7

Case-control/Nested case-control

Question 8

For observational studies, if groups organized by EXPOSURE STATUS, it is a __ study

Answer 8

Cohort

Question 9

For observational studies, if “together d/t a common factor”, it is a __ study

Answer 9

cohort

Question 10

For observational studies, if data collected across large population, it is a __ study

Answer 10

cross-sectional

Question 11

A case-control design is useful when studying a rare disease. It commonly generates an __ for each and an __ as measure of association

Answer 11

Odds of exposure

Odds ratio (OR)

Question 12

Case control studies are customarily conducted in a __ fashion.

Answer 12

Retrospective

Question 13

A __ study derived from w/in or out of a cohort or interventional study

Answer 13

Nested case control

disease/outcome subjects from ‘other’ study become the cases of a subsequent (different) study

Question 14

a __ design is useful when studying a rare exposure. Commonly generates the Risk of disease/outcome for each and a RR as measure of association

Answer 14

cohort

Question 15

Cohort studies can be conducted in a __ fashion

Answer 15

retrospective or prospectve (or both)

Question 16

In Case control, which boxes?

In Cohorts, which boxes?

Answer 16

Disease presence –> Column totals (A+C and B+D)

Exposure –> row totals (A+B and C+D)

Question 17

A Group with something in common, i.e., Birth/inception/exposure/etc. is characteristic of __

BIG STAR

Answer 17

cohort study

Framingham heart study, nurses health study

Question 18

Think of a __ study when the info gathered represents what is going on with disease AND exposures (at the same time) across the entire (a large) study population

Answer 18

x-sectional

“snap-shot” in time; examine relationships between disease AND exposure

Question 19

Any survey that says “National” is a __ study

Answer 19

X-sectional

Question 20

This interventional phase study is exploratory, investigational new drug, healthy volunteers, very small (<20), very short duration

Answer 20

0

Question 21

This interventional phase study is for investigational new drug, assess safety/tolerance and PK of or more dosages, can have healthy or disease volunteers (depends on disease), small N (20-80), short duration (few weeks)

Answer 21

1

Question 22

This interventional phase study is for investigation new drug in the indicated population. Assess effectiveness, diseased volunteers (narrow inclusion criteria for isolation of effects), larger N (100-300), short-medium duration (few wks to months)

Answer 22

2

Question 23

This interventional phase study is for investigational new drug, indicated population. Assess effectiveness, diseased volunteers (may expand inclusion criteria and comparison groups for delineation of effects; Various stat-perspectives can be taken in studies such as superiority, non superiority, and equivalency), larger N (500-3000), longer durations (few months to years)

Answer 23

3

Question 24

this interventional phase study is post FDA-approval. Registries/surverys also used in observational design

Answer 24

4

Question 25

this interventional study format has subjects randomly allocated ONCE into a single tx group

Answer 25

Simple

Question 26

this interventional study format has subjects randomly allocated into an initial group, then further randomly subdivided into a subgroup (multiple randomizations)

Answer 26

Factorial

useful in testing multiple hypotheses at the same time

Question 27

This interventional study format has subjects exclusively managed in a single tx group. No switching groups after initial randomization

Answer 27

Parallel

Question 28

This interventional study format has subjects forcibly switched to other tx group after initial tx assignment

Answer 28

X-over

Between & within group comparisons possible

Question 29

which group allocation procedure most commonly utilized?

Answer 29

Random –> subjects have equal probability of being assigned to each of the pre-defined intervention groups

Question 30

this form of randomization ensures balance within known confounding variables

Answer 30

Stratified

Question 31

This form of blinding is neither investigators nor study subjects are informed which intervention (tx) group subjects are in

Answer 31

Double blind

Question 32

Most conservative method of managing drop outs/lost to follow up by including them

Answer 32

intent to tx

• preserves randomization process
• maintains Power

Question 33

__ role is to protect human subjects from undue risk. All human subject studies MUST be reviewed by them PRIOR TO study starting

Answer 33

IRB

Question 34

__ role is as a semi-independent committee not involved with conduct of study but charged with reviewing data AS STUDY PROGRESSES to assess for undue risk of benefit

Answer 34

DSMB

can stop study early