General Methodological Concepts Of Research Flashcards
What are the two types of Study Design?
Interventional study design
-Investigator-selects interventions (exposure)
Observational Study design
- Researchers “observe” subject-elements occurring naturally or selected by individual
- Most observational study designs not able to prove causation
What is the most useful and appropriate study design?
It depends on the question being asked and the desired perspective.
Study design selection based on:
- Perspective of research question (Hypothesis)
- Ability/Desire of researcher to force group allocation (randomization)
- Ethics of methodology
- Efficiency and Practicality (time/resource commitment)
- Costs
- Validity of acquired information (Internal Validity)
- Applicability of acquired info to non-study patients (External Validity)
What is a population?
All individuals making up a common group; from which a sample (smaller set) can be obtained, if desired.
What is a sample?
A subset or portion of the full, complete population (“representatives”)
Study population selection based on:
- Research Hypothesis/Question
- Population of Interest
- Inclusion and Exclusion selection criteria (Interventional studies) and Case and Control group OR Exposed and Non-exposed group selection criteria (Observational studies)
What is a Null Hypothesis?
A research perspective which states there will be NO (true) difference between the groups being compared.
What various statistical-perspectives can be taken by the researcher for a Null Hypothesis?
- Superiority
- Non-inferiority
- Equivalency
What is a Probability sample?
-Every element in the population has a known (non-zero) probability of being included in sample
What is simple random sampling?
-Assigns random numbers, then take randomly-selected numbers to get desired sample size
OR
-Assign random numbers,then sequentially-list numbers and take desired sample size from top (or bottom) of listed numbers
What is systematic random sampling?
-Assign random numbers, then randomly sort these random numbers, then select highest (or lowest) number, then systematically, by a pre-determined sampling-interval take every Nth numbers to get desired sample size.
What is stratified simple random sampling?
-Stratify sampling frame by desired characteristic (e.g., Gender), then use Simple Random sampling to select desired sample size.
What is Stratified Disproportionate Random sampling?
- Disproportionately utilized 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
What is Multi-Stage random sampling?
-Uses Simple Random sampling at multiple stages towards selection
What is Cluster Multi-Stage random sampling?
-Same as Multi-Stage Random sampling but ALL “elements” clustered together (at any stage) are selected for inclusion
Ex: ALL Clinics in a zip code or ALL Households in a community
