Class #15: General Methodological Concepts of Research Flashcards
What is the Null Hypothesis (H0)?
A research perspective which states there will be NO (true) difference between the groups being compared.
>most conservative and commonly utilized
>various statistical-perspectives can be taken by the researcher:
-superiority
-noninferiority
-equivalency
**Researchers either accept or reject this perspective, based on results (data analysis) **
What is the alternative hypothesis (H1)?
A research perspective which states there will be a (true) difference between the groups being compared.
What are the two main types of study design? Also, what is the main difference between the 2?
Observational – study designs considered “natural”
Interventional – study designs considered “experimental”
**The main difference -> in observational there is NO researcher-forced group allocation.
in interventional there is researcher-forced group allocation.
What are the 5 sub-sets under observational study design?
Observational >cases (reports/series) >ecological >cross-sectional >case-control >cohort
What are the 5 sub-sets under interventional study design?
Interventional >pre-clinical >phase 1 >phase 2 >phase 3 >phase 4
What be the study design used if the investigator did not assign exposures?
Observational Study
What would the experimental design be if a researcher did assign exposures?
Experimental Study
What are the 6 things that study design selection is based on?
- Perspective of Research Question (hypothesis)
- Ability/Desire to force group allocation (randomization)
- Ethics of methodology
- Efficiency & Practicality
- Costs
- Validity of acquired information (internal & external)
If the study design of an experiment is an observational study, what would be the 3 types of analytical study design if the author wanted to compare study groups?
- Cohort Study
- Case-Control Study
- Cross-Sectional Study
During an observational study when the author is comparing between groups, what type of analytical study is being performed when looking at exposure and outcome at the same time?
Cross-Sectional Study
What is the definition of population?
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 population”, which is simply the final group of individuals selected for a study.
What is the definition of sample?
A subset or portion of the full, complete population (“representatives”).
>useful when studying the complete population is not feasible
>random processes commonly utilized to draw sample
What are the 4 key principles of bioethics?
- Autonomy
- Beneficence
- Justice
- Nonmaleficence
What are the 4 sub-sets in human studies that study population selection is based on?
- Research Hypothesis/Question
- Inclusion & Exclusion selection criteria (interventional studies) & Case and Control group OR Exposed and Non-Exposed group selection criteria (observational studies).
>desired vs. logical vs. plausible selection criteria
>these absolutely impact generalizability!
- external validity - Ethics
>principles of bioethics MUST be met…
- some don’t agree with use of placebo if a treatment is available
>recall Null Hypothesis perspectives…
- superiority
- noninferiority
- equivalency - Equipoise - genuine confidence that an intervention may be worthwhile (risk vs. benefit) in order to use it in humans
What is the requirement for a participant in a study to have autonomy?
Have self-rule/self-determination. Thus, participants must have full and complete understanding of the risks and benefits, and decide for ones-self, without outside influences.
What must researchers do to comply with nonmaleficence in a human study?
Researchers must not:
- withhold information - provide false information - exhibit professional incompetence
What report is the ethical conduct of research methodology based on?
1978; issued by National Commission for Protection of Human Subjects of Biomedical and Behavioral Research
What are the 3 guiding principles in ethical conduct of research methodology?
- respect for persons
- research should be voluntary, subjects autonomous
- beneficence
- research risks are justified by potential benefits
- justice
- risks and benefits of the research are equally distributed
What is the definition of consent and assent?
Consent -> agreement to participate, based on being fully and completely informed [given by mentally-capable individuals of legal consenting age (i.e., adults; age 18 in most states)]
Assent -> Agreement to participate, based on being fully and completely informed, given by mentally-capable individuals NOT able to give legal consent (i.e., children and adolescents)
-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.
Who determines what is ethical in conduct of research?
Institutional Review Board (IRB)
- sometimes referred to internationally as the “ethics committee”
- IRB’s role is to protect human subjects from undue risk (research not complying with principles of bioethics)
- all human subject studies MUST be reviewed by an IRB prior to study initiation
> observational and interventional studies (all use humans)
What agency administers and enforces the regulations of the IRB?
Office of Human Research Protections (OHRP)
What are the 3 levels of IRB review?
- Full Board - used for ALL interventional trials with more than minimal/no risk to patients.
>all medication-related studies - Expedited - minimal risk and/or no patient identifiers
- Exempt - no patient identifiers, low/no risk, de-identified dataset analysis, environmental studies, use of existing data/specimens (de-identified)
What is the Data Safety & Monitoring Board (DSMB)?
Semi-Independent Committee not involved with the conduct of the study but charged with reviewing study data AS STUDY PROGRESSES, to assess for undue risk or benefit.
- pre-determined review periods (interim analysis) - can stop study early, for either overly-positive or overly-negative findings
What are the two methodology of human studies?
Outcomes
- patient-oriented best
- individual vs. combined
Internal Validity
- assessments (measurements)
> scientifically-rigourous and standardized
* objective better than subjective assessments
> valid, accurate and reproducible
