Lecture 15 Research Concepts Flashcards
Study Design Selections Based On:
- perspective of research question (hypothesis)
- ability/desire to force group allocation (randomization)
- ethics of methodology
- efficiency and practicality (time/resource commitment)
- costs
- validity of acquired information (internal and external)
Null Hypothesis (Ho)
- a research perspective which states there will be no (true) difference between the groups being compared
- researchers either accept or reject this perspective based on results
- most conservative and commonly utilized
- superiority= my intervention is better than the other intervention
- non-inferiority= my intervention is just as good as the other (not better or worse, the same)
- equivalency= equal, just not as good as the really good drug but better than placebo
Alternative Hypothesis (H1)
-a research perspective which states there will be a (true) difference between the groups being compared
Typer 1 Error Vs Type 2 Error
1=False Positive
- reject the null but Ho (the null) is true
2=False Negative
-accept the null but H1 is true
Research Evidence Pyramid
(From increasing strength of evidence)
- Meta-analysis
- Systematic reviews
- Interventional Studies and Pragmatic trials
- Cohort
- Case-Control
- Cross-Sectional
- Ecological
- Case Series
- Case Reports
- Animal research
- In vitro (test tube)
Observational Study Design
“natural”
- researchers observe subject elements occurring naturally (or freely) selected by the individual
- most study designs are NOT able to prove causation
- there is NO researcher forced group allocation
Interventional Study
“experimental”
- investigator selects interventions (exposure)
- there IS researched forced group allocation (randomization process)
- more “rigorous” in ability to show cause and effect (demonstrates causation)
Examples of Observational
descriptive
- case reports/series
- ecological
analytic
- cross sectional
- case control
- cohort
Interventional Design
Randomized or non randomized
Analytical
-pre clinical phase 1 phase 2 phase 3 phase 4
-moving from phase 1-4:
1. population size continues to get larger
2. longer duration
3. change in focus (safety, efficacy, safety)
Human Study Subjects
- population= all individuals making up a common group from which a smaller sample can be obtained if desired
- sample= a subset or portion of the full, complete population “representatives” (random process to draw sample)
Study Population Selection Based On:
- research hypothesis/question
- inclusion and exclusion criteria
- case and control group
- exposed and non-exposed
- ethics
- equipoise (confidence that an intervention may be worthwhile)
- these absolutely impact generalizability (external validity)
- the more specific you get the less generalizability
4 Key Principles in Bioethics
- Autonomy= self rule, decide for ones-self, full understanding of risks/benefits
- Beneficence= to benefit/do good for the patient (not society)
- Justice= equal and fair treatment regardless of patient characteristics
- Nonmaleficence= Do not harm (researchers must not withhold info, provide false info, exhibit professional incompetence)
Belmont Report
issued by national commission for protection of human subjects of biomedical and behavioral research
-contains 3 guiding principals: respect for persons, beneficence, justice
Consent vs Assent
- consent= agreement to participate based on being fully informed (adults 18+)
- assent= agreement to participate based on being fully informed given by mentally capable individuals not able to give legal consent (children/mentally handicapped) *requires consent of parent or legal guardian
Institutional Review Board (IRB)
- ethics committee
- protect human subjects from undue risk
- regulated by federal laws developed by DHHS (department of health and human services)
- CFR (common federal rules) are followed
- enforced by OHRP (office of human research protection)
*all human studies MUST be reviewed by an IRB PRIOR to the study initiation
