Lecture 15: General Methodological Concepts Of Research Flashcards
List the major stages of research evidence period (in order of increasing evidence)
- Bench Research
- Animal Research (These first two don’t involve humans)
- Ecological
- Cross-Sectional
- Case Control
- Cohort
- Interventional Studies & Pragmatic Studies
So what is the most useful and appropriate study design?
IT DEPENDS on the QUESTION being asked and the desired perspective.
What are the two types study design and methodology?
- Quantitative: Numbers are used to represent data
- Qualitative: Words are used to represent data
Breaking All studies into two groups: this would be it.
Note: Surveys such as “Highly Agree, Disagree” are quantitive since they’re taking number rankings between 1 through 5 or whatever. Quantitative seems more common.
Qualitative Research: If you were giving an essay response and keywords and consistencies are reported are interpreted as qualitative. Seems much less common.
What are the two types of quantitative study designs?
- Interventional - Forced Allocation to study groups
- Researcher is more strict and controlling. Conditions are forced into certain situations and scenarios.
- Observational: No forced allocation to study groups
- Researchers don’t get as involved and allow results to form naturally. Don’t know of an example yet. However, should be obvious when it’s interventional.
Give an overview of Study Designs
- Various types of study designs & methodologies used by researchers
- Each design represents its own, unique way of harvesting information to answer a research question
- Every design has its STRENGTHS and WEAKNESSES.
Describe the selection-based approach for study designs
- Study design selection based on:
- 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; Generalizability)
- See Slide 8
What is what he calls the “Research Question”?
Research Question: (‘I wonder if….’ statement)
- Helps frame study intent and can direct researcher to more effective study design to answer question
Describe Null Hypothesis
- Null Hypothesis (H0): Researchers either ACCEPT or REJECT this perspective, based on results (data analysis)
- 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
3 potential comparisons to placebo/other drug:
- Better
- Equal
- Worse.
(Not actually represented by the bullet list)
For Noninferiority: When using placebos are unethical, researchers often go with “Not Worse”.
So those bullets represent goals. If it’s Not Superior, then it’s either equal or worse. So…Noninferiority seems to be the most uncertain one. Compared against something that’s proven to work.
Null hypothesis is always “No Effect”.
This is done this way to prevent falling into the habit of looking for something that’s not there.
Classic FDA strategy too. Hence the use of placebos.
Describe Alternative Hypothesis
Alternative Hypothesis (H1) - A research perspective which states there will be a (true) difference between the groups being compared
What are the two types of errors in inaccurately accepting or rejecting null hypothesis.
Type I Error (Alpha Error) = False positive; Such as a male patient being told he’s pregnant.
Type II Error (Beta Error) = False Negative; Such as a female pregnant women being told she’s not pregnant.
See Slide 12
What are some of the Main differences between Interventional and Observational Study Designs?
- Interventional study designs considered “experimental”
- Investigator-selects interventions (exposure)
- **There IS researcher-forced group allocation
- Randomization processes commonly utilized to accomplish this step
- Observational study designs considered “natural”
- Researchers “observe” subject-elements occurring naturally or selected by individual (naturally or freely)
- Useful for unethical study designs using forced interventions
- Most observational study designs not able to prove Causation
- ** There is NO researcher-forced group allocation
In human studies, what are the two subcategories of study subjects used?
- Whole Populations
- 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
- Samples:
- 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
In human studies, what is the population selection based on?
- Research Hypothesis/Question
- Population of Interest
- Group of individuals most useful and applicable to answer the research question
- INCLUSION & EXCLUSION selection criteria (Interventional studies) & Case & Control group OR Exposed & Non-Exposed group selection criteria (Observational studies)
- Desired vs. Logical vs. Plausible selection criteria
- These ABSOLUTELY impact generalizability!
- External Validity
In human studies, what Ethical requirements are needed for a study population selection?
- 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
Define EQUIPOISE
(Very NTK)
** Genuine confidence that an intervention may be worthwhile (risk vs. benefit) in order to use it in humans
Note: Definition is definite test question. Preferably reworded.
States that the study you’re doing holds the potential for more benefits and a higher risk/reward ratio.
Controversy states that using placebos violates equipoise principles.
