Exam 1 Flashcards
Internal validity
- the degree of confidence a researcher has that the changes observed in the dependent variable are because of the independent variable
- degree to which study outcomes can be explained by differences in assigned intervention
External validity
Refers to the extent to which the results of a study can be generalized to other settings/larger population
Causality
The outcome is the result of the treatment
What are the 9 criteria for casual relationships
Temporality
Strength
Biological gradient
Consistency
Specificity
Plausibility
Coherence
Analogy
Experiment
(ACCEPTS Some Bitches)
What is meant by temporality
Cause occurs before the outcome
What is meant by strength
Plausibility of causation increases with the strength of the relationship
What is meant by biological gradient
Linear relationship like a dose response is observed
What is meant by consistency
Casual relationship exists in different settings
What is meant by specificity
One to one relationship between cause and effect
What is meant by plausibility
Reasonable biological explanation
What is meant by coherence
Explained by existing knowledge
What are descriptive studies
Describe/summarize info without making any casual inferences
What is meant by experiment
Evidence that cause is controlled by the researcher
What is meant by analogy
Effect is similar to accepted phenomena
What is the purpose of a study
- to describe a phenomena
- provide casual interpretation of existing phenomenon
What are the 5 Ws of descriptive studies
Who (demographic)
What (case definition)
Why (clues about casual mechanism)
When (time period)
Where (place of occurrence)
So What (significance)
What are analytical studies
- aimed at understanding casual mechanism
- can involve both experimental and observational designs
What is common in basic research
Experimental designs
What is seen in clinical research
Both experimental and observational designs
What is most commonly used in experimental design
Randomized controlled trials (RCT)
What are the two essential elements of randomized controlled trials
Randomization and prospective
What is the gold standard in evaluating safety and efficacy of an intervention
Randomized controlled trials (RCT)
What is the independent variable
Exposure of interest, like medication or intervention
What types of data can be utilized in observational studies
- primary data (interviews, surveys)
- secondary data (medical charts)
What is a limitation of RCTs
Restricted external validity; may not be generalizable to real world settings
What is the key element of observational studies
Non-randomization of independent variable
What can case reports lead to
Generation of a hypothesis
What does a case report involve
A study of a single case of a new disease of manifestation
When are cross sectional studies inappropriate to be used
To study causality
How is a cross sectional study conducted
Exposure and outcome are measured at the same point in time
Where are case and controls identified from in case-control studies
From the same source population
When are cross sectional studies inappropriate to be used
To study causality
What is the design of choice to study a rare outcome and when there is a long latency period
Case control studies
How are cohort studies conducted
Follow exposed and unexposed over a period until development of outcome
How are the groups defined in cohort studies
Exposure status (exposed vs unexposed)
What does a cohort study provide a measure of
Relative risk
What is a retrospective (historic) cohort study
Uses previously collected data
What is a prospective cohort study
Groups followed in the future
What is a limitation of cohort studies
No randomization, so vulnerable to selection bias
What is quantitative data
Numerical or countable information
What is qualitative data
Words or textual information
What are primary methods
- collects data specifically for the research question
- surveys and observations
What are secondary methods
- data that was collected for a different purpose
- medical charts and medical claims
What guides the choice of data collection method
- research question
- population of interest
- availability and feasibility of method
- cost
What are the strengths of secondary methods
- easier to conduct
- less costly
What are the weaknesses of secondary methods
- may not include needed variables
- difficult to interpret (may lack info)
What are the strengths of primary methods
Data collected fits need of study and can be tailored
What are the weaknesses of primary methods
Resource intensive (cost, time)
What is reliability
Consistency and reproducibility of a given result
What is validity
- extent to which it measures what is intended
- degree to which findings represent the truth
What are the strengths of open ended questions
Provides flexibility to patient
What are the weaknesses of open ended question
- unsuitable for statistical analysis
- challenging
- time consuming
What are the strengths of close ended questions
- provides specific set of responses
- easy to code and use in statistical analysis
What is an unobtrusive observation
Participant is unaware of the observer
What are the weaknesses of close ended questions
Limits option choices
What is an obtrusive observation
Participant is aware that he/she is being observed
What is the:
- strongest type of primary study
- most common type of trial used to determine efficacy
- required by the FDA
?
Randomized controlled trials (RCTs)
What are RCTs referred to as
Phase III studies or pivotal trials
What does bias refer to
Systematic errors
What threatens the internal validity of a study the most
Biases
What is the purpose of including a control group
Strengthening internal validity
How do you get selection bias
Preferential enrollment
When is selection bias the most problematic
Retrospective trials or in observational designs
What is the most effective way to reduce selection bias
Randomization
What is the Hawthorne effect
Subjects modify their behavior because of the fact that they are being studied or observed
What is the placebo effect
Leads to favorable response because patients believe it should work
What is the best way to minimize the Hawthorne and placebo effect
Control group and blind participants
What is history bias
External events (death of family, loss of job) that occur during the course of the study that can alter the outcome
What is maturation bias
Normal changes in study participants over time
What is maturation bias
Normal changes in study participants over time
What is attrition bias
- differential dropout of patients in treatment and control groups
- controlled by enrolling more patients
What is testing bias and how is it minimized
- improvements that can occur by repeated testing
- participant may alter behaviors because of monitoring
- minimized by having consistent assessment methods by unbiased investigators or use control group that is similarly influenced
What is regression to the mean and how is it minimized
- initial measurements of a variable are extremely different from population mean, but subsequent measurements are closer to the average
- avoid extreme groups and use control drugs
(IRAT Q): a scientific study designed to test a medical intervention in humans is known as
A clinical trial
(IRAT Q): Case reports are effective in
Generating a hypothesis
(IRAT Q): Cohort studies mirror the clinical trial design in the following way
They start with groups exposed and unexposed
(IRAT Q): Which research deals with the areas of inquiry like pharmacology, med chem, pharmaceutics
Applied
(IRAT Q): Which of the following is NOT an objective of case reports
- disease identification
- adverse reaction reporting
- quality assurance
- medication efficacy testing
Medication efficacy testing
(IRAT Q): _____ refers to the collection of information based on human experience
Empiricism
(IRAT Q): Which is considered to be the gold standard in evaluating the safety and efficacy of an intervention
Randomized clinical trials
(IRAT Q): Equitable selection is based on which ethical principle
Justice, because the risks of research should be shared equally
(IRAT Q): Which of the following other observational study designs observe study participants at only one point in time
Cross-sectional study design
(IRAT Q): Which of the following are true regarding consent for the publication of a case report
If a patient has passed away, next of kin should be contacted for consent
(IRAT Q): ______ reflects the extent to which the clinical outcome of interest (dependent variable) in a study is caused by the treatment (independent variable)
Internal validity
(IRAT Q): The ____ of an event is calculated as a ratio between two incidence proportions or two incidence rates
Relative risk
(IRAT Q): Which of the following is included in evidence based medicine
Research evidence
Clinical expertise
Patient values
All of these are correct
(IRAT Q): At what point of the drug development process does a patient request a developmental drug as part of the “right to try” act
After phase I trials
(IRAT Q): A study’s ____ measures the capacity to detect a difference in the study groups if a true difference exists
Power
(IRAT Q): Which study design is universally superior to other study designs
None
(IRAT Q): Which of the following sampling strategies has the best possibility to result in a representative sample of participants from a source population
- Convenience sampling
- Purposive sampling
- Random sampling
- Both convenience and random sampling
Random sampling
In what phase of clinical trials does the evaluation of safety data take place
Phase I
Phase II
Phase III
(IRAT Q): If a figure or table is included in a case report, which of the following is correct
A table or figure should be able to stand on its own
(IRAT Q): A major difference between a case series and case report is
Sample size
