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E2 - Epi > Epi - L1 - General Concepts of Research > Flashcards

Epi - L1 - General Concepts of Research Flashcards

1
Q

Study design & methodology

A

quantitative vs. qualitative

numbers as data vs words as data

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2
Q

which of the two study designs uses forced allocations to study group?

A

interventional studies (observational does NOT force allocation to study groups)

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3
Q

interventional studies

A
  • considered “experimental”
  • investigator selects interventions or exposure
  • there IS researcher-forced group allocation and randomization processes are commonly utilized to accomplish this
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4
Q

observational studies

A
  • considered “natural”
  • useful for unethical study designs using forced interventions
  • ** most of these studies are not able to prove Causation
  • there is NO RESEARCHER-FORCED group allocation
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5
Q

interventional study design is broken into how many phases, and in which way does the evidence increase?

A

Phase 0, 1, 2, 3, 4; increases from 0-4

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6
Q

what type of observational studies are there?

A

case reports/series, ecological, cross-sectional, case-control, cohort; increases from left to right

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7
Q

what is the most useful and appropriate study design?

A

it depends on the question being asked and the desired perspective;

FDA picks interventional studies

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8
Q

study design selection is based on:

A
  • perspective of research question (hypothesis)
  • ability/ desire of researcher to force group allocation (randomization)
  • ethics of methodology
  • efficiency & practicality (time/resource commitment)
  • costs
  • validity of acquired information (internal validity)
  • applicability of acquired information to non-study patients (external validity; generalization)
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9
Q

human studies: study subjects:

A
  • population

- sample

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10
Q

population

A

all individuals making up a common group; from which a sample (smaller set) can be obtained, if desired

  • not to be confused with the ‘study pop’ which is the final group of individuals selected for the study
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11
Q

sample

A

a subset or portion of the full, complete population (“representatives”)

  • useful when studying the complete pop is not feasible
  • random processes commonly utilized to draw sample
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12
Q

what is the study population selection based on?

A
  • research hypothesis / question of interest
  • population of interest
    • group of individuals most useful and applicable to answer the research question
  • INCLUSION & EXCLUSION selection criteria (interventional studies) and CASE & CONTROL/ EXPOSED & UNEXPOSED group selectroin criteria (observational studies)
    • depends on what the desired, logical or possible selection criteria is available
    • these absolutely impact generalizability
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13
Q

What is the Null Hypothesis?

A

a research perspective which states there will be NO (true) difference between the groups being compared
- most conservative and commonly utilized

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14
Q

what statistical-perspectives can be taken by the researcher when it comes to a null hypothesis?

A
  1. superiority
  2. noninferiority
  3. equivalency
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15
Q

what is the most common sampling scheme?

A

probability samples

- every element in the pop has a known (nonzero) probablity of being included in the sample

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16
Q

what are 6 examples of probability sampling schemes?

A

all random sampling:

  1. simple
  2. systematic
  3. stratified simple
  4. stratified disproportionate
  5. multi-stage
  6. cluster multi-stage
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17
Q

simple random sampling

A
  • flip of the coin
  • number out of the hat
  • assign random numbers, then take randomly-selected numbers to get desired sample size
  • assign random numbers, then sequentially-list numbers and take desired sample size from top (or bottom) of listed numbers
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18
Q

systematic random sampling

A

assign random numbers, then randomly sort these random numbers, then select highest (or lowest) number, then SYSTEMATICALLY, by pre-determined sampling-interval, take every Nth number to get desired sample size

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19
Q

Stratified Simple random sampling

A
  • STRATIFY sampling frame by desired characteristic (e.g., gender), then use SIMPLE random sampling to select desired sample size.
20
Q

Stratified Disproportionate Random Sampling

A
  • DISPROPORTIONATELY utilizes STRATIFIED SIMPLE random sampling when baseline population is not at the desired proportional percentages to the referent population

= stratified sample ‘weighted’ to return sample population back to baseline population
- useful for ‘over-sampling’

21
Q

Multi-Stage random sampling

A

uses SIMPLE random sampling at MULTIPLE-STAGES towards patient selection

  • regions/counties (primary sampling unit; PSU)
  • city blocks/ zip codes (secondary SU; SSU)
  • clinic/ hospital/ household
  • individual/ occurence
22
Q

Cluster Multi-Stage random sampling

A

same as MULTI-STAGE but ALL ‘elements’ clustered together (at any stage) are selected for inclusion

  • ALL clinics in a zip code
  • ALL households in a community
23
Q

what is another type of sampling scheme?

A

Non-probability sampling schemes

24
Q

Non-probability sampling schemes

A

‘Quasi-systematic’ or ‘Convenience’ samples (they are not really completely random or fully probabilistic)

  • decide on what fraction of population is to be sampled and how they will be sampled
    • eg: all persons whose last name begins with “m-z”
      all members of a professional business association

concern: there is some known or unknown order to the sample generated by the selected scheme which may introduce bias (selection bias)

25
Q

Methodology of Study

A

OUTCOMES
- patient-orientated (vs. disease-oriented) outcomes are most important and useful
= individual vs. combined outcomes

26
Q

Methodology of study

A

INTERNAL VALIDITY (methods ‘inside’ study)

  • assessments (measurements)
    • scientifically-rigorous and standardized
      • objective better than subjective assessments
  • accurate and reproducible and scientifically
27
Q

what else is the study population based on?

A

Ethics

- principles of bioethics must be met

28
Q

equipoise

A

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

29
Q

what are the 4 key principles of bioethics?

A
  1. autonomy
  2. beneficence
  3. justice
  4. nonmaleficence
30
Q

autonomy

A

self rule/ self-determination. the participant must..

  • be able to decide for ones-self (without influence, or coercion)
  • have full and complete understanding of the risk and benefits (no misinformation, incomplete info, or ineffectively-conveyed information)
31
Q

beneficence

A

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

32
Q

justice

A

equal and fair treatment regardless of patient characteristics

33
Q

Nonmaleficence

A

do no harm. researchers must not..

  • withhold information
  • provide false information
  • exhibit professional incompetence
34
Q

Ethical conduct of research methodology:

A

Belmont Report - 1978, issued by National Commission of Protection of Human Subjects of Biomedical and Behavioral Research

35
Q

what are the 3 guiding principles of the Belmont Report?

A
  1. Respect for persons - research should be voluntary, subjects autonomous
  2. beneficence - research risks are justified by potential benefits
  3. Justice - risks and benefits of the research are equally distributed
36
Q

What two ways are participants able to agree to participate in interventional studies?

A

Consent and Assent; (1) agreement to participate, based on being fully informed, of legal age x>18; (2) if the participant is not 18, researcher must get consent of parent, then assent (permission) from minor.

37
Q

who determines the ethical conduct of research?

A

IRB - Institutional Review Board aka Ethics Committee

  • their role is to protect human subjects from undue risk
  • ALL human subject studies MUST be reviewed by an IRB prior to study initiation (both observational and interventional studies, if humans are included)
38
Q

what regulates the IRB?

A

IRB’s are regulated by Federal statutes (laws and regulations) developed by the Department of Health and Human Services (DHHS)

  • rules are referred to by CFR (common federal rules)
  • ## applies to all studies funded by federal govn; standards also usually apply to studies reviewed by an IRB
39
Q

What agency administers and enforces regulations?

A

OHRP - the Office of Human Research Protections

- OHRP can pull funding from institutions/ studies

40
Q

What are the different levels of IRB reviews?

A

full board
expedited
exempt

41
Q

full board

A

used for ALL interventional trials with more than minimal risk to patients; for large studies; time extensive; needles, drugs, scans, invasive stuff

42
Q

expedited

A

minimal risk and/or no patient identifiers (like surveys)

43
Q

Exempt

A

no patient identifiers, low/no risk, de-identified dataset analysis, environmental studies, use of existing data/ specimens (de-identified)

44
Q

whats the main differences between the 3 levels of review?

A
  • number of members and time for Committee Review/ approval

- level of detail to the documentation needed for review

45
Q

who decides the level of review?

A

DSMB - data safety and monitoring board

  • semi-independent committee not involved with the conduct of the study but charged with reviewing study data AS STUDY PROGRESSES (they get involved AFTER the study has gotten going), to assess for undue Risk/Benefit between groups
    • pre-determined review periods
    • can stop study early for either overly-positive or overly-negative findings in one or more groups

E2 - Epi (6 decks)

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