Lecture 7: General Methodologies Of Study Design

Question 1

Two types of quantitative studies

Answer 1

Interventional and observational

Question 2

What occurs in an interventional study?

Answer 2

Researchers forces people into groups— typically by a type of randomization

Leads to increasing evidence and hopefully causation

Question 3

What’s the basis of observational studies?

Answer 3

“Natural” study— people are NOT forced into groups.

Useful for when group allocation is unethical.

Question 4

What is a weakness of observational studies?

Answer 4

Most are not able to prove causation

Question 5

How do you decide which type of study to use?

Answer 5

It all depends on the RESEARCH QUESTION that you are trying to answer.

Question 6

How are subjects chosen for certain studies?

Answer 6

Depends on:
Research question
Population of interest
Inclusion/exclusion criteria
Case/control OR exposed/unexposed groups

Question 7

How does selection criteria impact a study?

Answer 7

Selection criteria is inclusion/exclusion criteria. It affects generalizability and external validity

EX: mental health exchangeability

Question 8

Types of Null hypotheses

Answer 8

Superiority
Non-inferiority
Equivalency

Question 9

Superiority question/null hypothesis

Answer 9

Question: is my drug SUPERIOR to placebo/another drug?

Null hypothesis: drug is NOT superior to placebo/another drug

Question 10

Non-inferiority question/null hypothesis

Answer 10

Question: is my drug NOT WORSE than another drug?

Null hypothesis: drug IS worse than other drug

Question 11

Equivalency question/null hypothesis

Answer 11

Question: is my drug equal to other drug?

Null Hypothesis: drug is NOT equal to other drug

Question 12

What are the different types of sampling/randomization?

Answer 12

Simple random
Systematic random
Stratified simple random
Stratified disproportionate random
Multi-stage random
Cluster multi-stage random
Quasi-systematic

Question 13

Simple random

Answer 13

Assigned numbers then randomly pick numbers

Question 14

Systematic random

Answer 14

Assign random numbers and then randomly sort the numbers, then systematically choose desired sample

Ex: top 10, bottom 10, every 3rd, etc.

Question 15

Stratified simple random

Answer 15

Framed by desired characteristic, then use simple random to select desired sample size

Ex: stratified by gender

Question 16

Stratified disproportionate random

Answer 16

Disproportionately uses stratified simple random sampling when baseline pop is not as desired proportional percentages to the referent population

“Weighted” to return to baseline
Useful for over-sampling

Ex: adding/removing based on race to mimic USA population

Question 17

Multi-stage random

Answer 17

Simple at many stages in succession

EX: random region —> random city —> random hospital —> random incident

Question 18

Cluster multi-stage random

Answer 18

ALL elements are clustered together are selected for inclusion

EX: ALL hospitals in Overland Park, ALL households in community

Question 19

Quasi-systematic

Answer 19

A NON-PROBABILITY sampling scheme

First come first served; mostly based on convenience— not really completely random

Weakness: opportunity for BIAS (selection bias)

Question 20

What is a research question?

Answer 20

“I wonder if…” statement
Helps frame your study and direct researchers to selecting and developing an effective stud design to answer the question.

Question 21

What is study design based on?

Answer 21

Hypothesis
Ability/desire of researcher to force groups (randomization)
Ethics of methodoligy
Efficacy/practicality
Costs
Validity of acquired info (internal validity)
Applicability of acquired information (external validity

Question 22

Population

Answer 22

All individuals making up a common group from which a smaller sample can be obtained, if desired

Question 23

Sample

Answer 23

“Study population”

A subset or portion of the full, complete population

Question 24

internal validity

Answer 24

methods inside study

assessments
accurate and reproduciblt

Question 25

equipoise

Answer 25

genuine confidence that an intervention may be worthwhile (risk vs. benefit) in order to use it in humans

Question 26

what are the 4 principles of bioethics?

Answer 26

autonomy, beneficence, justice, nonmaleficence

Question 27

autonomy

Answer 27

must decide for oneself to participate and have full and complete understanding of risk/benefits

Question 28

beneficence

Answer 28

to benefit, or do good for the patient (NOT society)

Question 29

justice

Answer 29

equal and fair treatment regardless of patient characteristics

Question 30

nonmaleficence

Answer 30

do no harm; researchers must not….

withhold information, provide false information, or exhibit professional incompetence

Question 31

consent

Answer 31

agreement to participate based on being fully informed and of legal consenting age
–adults age 18+

Question 32

assent

Answer 32

agreement to participate, based on being fully informed and given by mentally-capable individuals NOT able to give consent
–children and adolescents

Question 33

IRB

Answer 33

institutional review board–> ethics committee
GOAL: to protect human subjects
must be done prior to start of study

risk/benefit AND 4 ethical principles MUST be met.

Question 34

who develops IRB laws

Answer 34

the department of health and human services (DHHS)

Question 35

who enforces IRB laws

Answer 35

office of human research protections (OHRP)

Question 36

what are the different levels of IRB review

Answer 36

full board
expedited
exempt

Question 37

full board review

Answer 37

used for ALL interventional trials with more than minimal risk to patients
LOTS of review is necessary.
used when: pills given, needles used, CTs needed, etc.

Question 38

expedited

Answer 38

minimal risk and no patient identifiers

used for: surveys –> ensures no traumatic questions or extreme measures are taken

Question 39

exempt

Answer 39

no patient identifiers, low/no risk, uses existing data/specimens (de-identified)
example: crunching numbers from CDC

Question 40

who decides what level of review to use?

Answer 40

data safety and monitoring board (DSMB)

can stop study early if too much harm/too much benefit is occurring during study.