General Methodological Concepts of Research

Question 1

What is the difference b/w quantitative and qualitative studies? Which one is most common?

Answer 1

Quantitative = numbers represent data (can convert words to #s) - most common Qualitative = words used to represent data (don’t convert to #s)

Question 2

What is the primary difference b/w observational and interventional study designs?

Answer 2

-Interventional = forced allocation to study groups (we intervene and put them in a group) -Observational = no forced allocation to study groups (natural selection)

Question 3

What study design is considered “experimental?”

Answer 3

Interventional - trying to answer a research Q with a study - IS researcher-forced group allocation; usually accomplished by randomization

Question 4

What study design is considered “natural?”

Answer 4

Observational -researchers observe subject elements occurring naturally or freely - most not able to prove causation -NO researcher forced group allocation

Question 5

Which study, interventional or observation, can prove causation? Which would be at the top of the research evidence pyramid?

Answer 5

-Interventional and interventional

Question 6

Interventional studies include:

Answer 6

Phase 0-4, w/ increasing strength of evidence (so phase 4 has most strength of evidence)

Question 7

Observational studies include:

Answer 7

-Case reports/series -ecological (not impt) -cross-sectional -case control -cohort (so highest strength of evidence) increasing strength of evidence going down this group

Question 8

What is the biggest determinant in selecting/developing an effective study design?

Answer 8

The research question

Question 9

What is the selection of study design and methods based on?

Answer 9

-research Q -forced allocation (randomization) or not -ethics -cost -efficiency/practibility -internal validity -applicability (external validity, generalizability)

Question 10

Population definition

Answer 10

All ppl making up a common group; from which a sample (smaller set) can be obtained if desired

Question 11

Study population

Answer 11

the final group of ppl selected for a study

Question 12

Sample definition

Answer 12

a subset or portion of the full complete population “representatives” of dz state -useful when studying the complete population is not feasible

Question 13

Inclusion & exclusion criteria are used for what type of study? (when selecting study popln)

Answer 13

Interventional studies

Question 14

Case and Control OR Exposed and Nonexposed critera are used for which type of study? (when selecting study popln)

Answer 14

Observational studies

Question 15

What is a null hypothesis? Do researchers want to prove the null hypothesis right or wrong?

Answer 15

-There is no (true) difference between the groups being compared -researchers want to prove the null wrong (so they either reject or don’t reject this perspective) ex) Is two drugs better than one? Null = Two drugs are not better than one

Question 16

What are the 3 other statistical perspectives or outcomes?

Answer 16

-Superiority = better (common/classic) -Non-inferiority = worse than hypothesis - Equivalency= equal to hypothesis (not talking about null hypothesis here)

Question 17

In which study is the outcome already known?

Answer 17

Retrospective -goal in assessing past Hx of some activity (exposure/tx)

Question 18

Which study, prospective or retrospective, is used by all interventional studies?

Answer 18

prospective studies

Question 19

Probability sample:

Answer 19

every element in the popln has a known (non-zero) probability of being included in sample -most common -equal probability = same chance

Question 20

Examples of probability sampling schemes

Answer 20

1) Simple Random sampling
- assign random #s–>take randomly selected #s to get desired sample size
- like flipping a coin
2) Stratified sampling
- stratify sampling frame by desired characteristics–>use simple random sampling to select
- make sure the characteristics are balanced (ex- same amount of males and females)
3) Multi-stage random sampling
- uses simple random sampling at multiple-stages towards pt selection
- regions/counties–>city blocks

Question 21

What category of sampling schemes do ‘Qausi-Systematic’ or ‘Convenience’ belong to?

Answer 21

Nonprobability sampling schemes -decide on what fraction of popln is to be sampled and how they will be sampled -there is a method, but not probabilistic - ex) All ppl who attend clinic on M/W/F

Question 22

What type of bias may be introduced when using non probabilistic sampling schemes?

Answer 22

Selection bias - bc there is some known/unknown order to the sample generated by the selected scheme

Question 23

What is internal validity?

Answer 23

Methods Inside the study - is this the best way to assess an outcome? - scientifically rigorous and standardized -accurate and reproducible -clinically applicable

Question 24

What is equipoise? Whats its use in terms of the use of placebo therapy?

Answer 24

-Genuine confidence that an intervention is worthwhile in order to use it in humans (risk vs benefit) -Some don’t agree with use of placebo if a tx is available, bc they think having ppl use the placebo is putting them at more risk than the ppl receiving tx *** If researcher knows one tx is superior to another, the researcher has to give the better tx**

Question 25

What are the 4 principles of bioethics

Answer 25

1) Autonomy = self-rule, self-determination; participants must DECIDE FOR ONES-SELF w/o outside influence 2) Beneficence = benefit the individual pt (not society) 3) Justice = equal and fair tx regardless of pt characteristics 4) Nonmaleficence = do no harm (cannot withhold info, provide false info)

Question 26

\_\_\_\_\_\_\_ issued by National Commission for Protection of Human subjects of biomedical and behavioral research (1978). What are the 3 principles?

Answer 26

Belmont report -Respect for persons -- Autonomy (participation should be voluntary) -Beneficence (risks justified by pot. benefits) -Justice (risk and benefits are equally distributed)

Question 27

Consent?

Answer 27

Agreement to participate based on being fully and completely informed (given by mentally-capable individuals of LEGAl consenting age)

Question 28

Assent?

Answer 28

Agreement to participate based on being fully informed, given by ppl NOT able to give legal consent -Children or adults not capable of giving consent requires the consent of the parent or legal guardian and the assent of the potential study subject

Question 29

Who determines the ethical conduct of research? Who holds ultimate decision on level of protocol review?

Answer 29

-IRB = Institutional review board -IRB

Question 30

Which group reviews before human subject studies start? Which group reviews study data as the study is in progress?

Answer 30

-IRB (b4) -DSMB (as it is progressing)

Question 31

What does the IRB do?

Answer 31

Performs the ethical determination \*\*\*"Ethics Committee" -ROLE = protect human subjects from undue risk - ALL human studies need to be IRB approved before starting -regulated by Federal statues - verify if the 4 principles of bioethics have been met b4 the study starts

Question 32

What are the levels of IRB review and their differences?

Answer 32

**-Full board** = all interventional trials with _more than minimal risk to patients_ (_high risk to its patients_)(drug/product/device approval) **-Expedited** = _minimal-moderate risk_; with or w/o pt identifiers (still looked at but the paperwork is not as heavy and board can get though it more quickly) **-Exempt** = _low/no risk,_ no pt identifiers, de-identified dataset analysis, use of existing data/specimens (samples/medical records already there)

Question 33

What does DSMB do?

Answer 33

**Data Safety and Monitoring Board** - review study data as study progresses, **assessing for undue risk or benefit b/w groups** - has p_re-determined time intervals for evaluation_ - can stop study early for either overly-(+) or overly-(-) findings in one or more groups