[2] Class 15: General Methodological Concepts Of Research Flashcards
What does the research evidence pyramid tell us?
The increasing strength of evidence based on design of research
What is the most useful and appropriate study design?
It depends
Study design uses numbers to represent data
Quantitative
Study design uses words to represent data
Qualitative
2 forms of quantitative study design
Interventional
Observational
Study design forced allocation to study groups
Interventional
Study design that does not force allocation to study groups
Observational
Study design selection can depend on:
Hypothesis Force group allocation (randomization?) Ethics Efficiency and practicality Costs! Validity of acquired info.-internal Generalizability=external validity
Helps frame study intent and can direct researcher to more effective study design to answer question
“I wonder if..”
A research perspective which states there will be no difference between the groups being compared
Null hypothesis
Statistical perspective that one Tx/exposure is better
Superiority
Statistical perspective that tries to prove a Tx/exposure is atleast as good as the other
Noninferiority
statistical perspective that one Tx/exposure is equivalent
Equivalency
Rejecting the null when you shouldn’t have
Type I error
False positive
Not rejecting the null when you should have
Type II error
false negative
If there is randomization, what type of study design is being looked at ?
Interventional
Study design considered “natural”- subject selected elements
Useful for unethical study designs
No researcher forced group allocation
Observational
Can observational study designs prove causation?
Most of the time=NO
Interventional study steps increasing evidence:
Pre-clinical [phase 0] Phase 1 2 3 4
Observation study steps increasing evidence:
Case reports/series Cross-sectional Ecological Case-control Cohort
All individuals making up a common group, from which a sample can be obtained
Population
A subset of the full, complete population
“Representatives”
Sample
Study population or sample picked by:
Hypothesis
Population of interest
Most useful group of ppl
Inclusion/exclusion selection criteria [interventional studies]
Case/control or exposed/nonexposed [observational]
Ethics
Selection criteria can affect what?
generalizability=
External validity
Genuine confidence that an intervention may be worthwhile [risk v. Benefit] in order to use it in humans
Equipoise
4 key principles of bioethics:
Nonmaleficence
Autonomy
Beneficence
Justice
Self-rule: deciding for oneself w/o outside influence w/ full/complete understanding of risks/benefits
Autonomy
To benefit, or do good for, the patient [not society]
Beneficence
Equal and fair Tx regardless of patient characteristics
Justice
Do no harm. Researchers can’t:
Withhold info.
Provide false info.
Exhibit professional incompetence
Nonmaleficence
1978 issued by national commission for protection of human subjects of biomedical /behavioral research- summarizes ethical principles and guidelines
Belmont report
Belmont report 3 guiding principles:
-Respect for persons- research should be voluntary
- Beneficence
- Justice
Agreement to participate, based on being fully and completely informed- by individual of legal age
Consent
Agreement to participate, based on being fully and completely informed, given by mentally-capable individuals not able to give legal consent (children)
Assent
Who determines if research is ethical?
IRB: Institutional Review Board “ethics committee”
Do all human subject studies have to be reviewed by an IRB?
YES!
How’re IRB regulated?
Federal statutes developed by department of health and human services (DHHS)
Who enforces laws/regulations on IRB’s?
The office of human research protections (OHRP)
Mindset when beginning study w/ regard to null
Mindset is opposite the null…want to set out to prove something, but null says there’s no difference
What do IRB’s look for when reviewing?
4 key principles of bioethics: Autonomy Beneficence Justice Nonmaleficence
Levels of IRB:
Full board
Expedited
Exempt
Level of IRB: used for ALL interventional trials w/ > minimal risk to patients…ton of documentation:
Full board
Level of IRB w/ minimal risk and/or no patient identifiers
Expedited
Level of IRB, no patient identifiers, low/no risk, deidentified dataset analysis, environmental studies, use of existing data/specimens [deidentified]
Exempt
What is the main differences btw the levels of IRB’s:
of members and time for committee review/approval
Level of detail to documentation needed for review
Who decides the level of IRB?
Data safety and monitoring board (DSMB)
Semi-independent committee not involved w/ the conduct of the study but charged w/ reviewing study data as study progresses, to assess for undue risk/benefit btw groups
Data safety and monitoring board (DSMB)
-looking out for people in the study.
Types of outcomes from a study
Patient-oriented v. Disease oriented
Individual v combined outcomes
Outcomes that patients view as important
Patient-oriented
Can be difficult to discern the outcome if this is used b/c different outcomes can have different rates of occurrence
Combined outcomes
Scientifically-rigorous and standardized
Objective>subjective
Accurate/reproducible/scientifically inside the study
Internal validity
What section of the study is most pertinent to internal validity?
Method. Most boring but if the procedure is wrong it is not valid
Putting many studies together and making global recommendations from them:
Meta-analyses
Similar to a book report on “37” articles
Systematic review
