Study Design Terminology Flashcards
Descriptive:
Employs observation and surveys.
- ‘Person, place and time’
- Observational
- What
- Who
- Where
- When
Analytic:
Uses statistical, mathematical, or computational techniques
- Associations: exposures
and outcomes - Causation
- Observational or
intervention studies - Why
Prevalence:
the proportion of a defined population who have a
disease at a point in time
What is the GATE frame?
Graphic Appraisal Tool for
Epidemiological studies
What is included within the GATE frame? (PECOT)
- population
- exposure/comparison
- outcome
- time
Ecological fallacy:
e.g. if a specific neighbourhood has a high crime rate, one might assume that any resident living in that area is more likely to commit a crime.
Temporal Sequence:
the order in which events occur over time
Prevalence equation
= (no. of ppl with disease at time point)/(total no. of ppl in population)
Guts of analytic epidemiology?
Is the exposure associated with the outcome? = Does the exposure increase or decrease the occurrence of the outcome?
What does PECOT stand for?
Population Exposure Comparison Outcome Time
Relative risk
How many times as likely is the exposed group to develop the outcome than the comparison group
What is relative risk equal to?
Ratio of the incidences (IExposed/
IComparison)
What is the null value?
Exposure doesn’t change occurrence of outcome, so no association between exposure and outcome
What is the null value of relative risk?
1
What does a relative risk value higher than 1 mean?
If outcome is bad it is a risk factor
What does a relative risk value lower than 1 mean?
If outcome is bad it is a protective factor
How do you interpret relative risk?
The exposed group were X as likely to develop the outcome compared to control group
Risk difference (attributable risk)
How many extra/fewer cases of the outcome in the exposed group are
attributable to the exposure
How to report risk difference?
There were X extra/fewer cases if outcome in exposed group in comparison
(Report differently for incidence proportion and
incidence rate)
Aetiology
the cause, set of causes, or manner of causation of a disease or condition.
What does relative risk provide?
Clues to aetiology (causes)
Strength of association
What does Risk Difference provide?
Impact of exposure
Impact of removing exposure
Observational
observe people’s exposures and what happens to them
Measures of occurrence
Incidence proportion (IP)
Incidence rate (IR)
Measures of association
Relative risk
Risk difference (attributable risk)
Incidence proportion:
Number of people who develop
the disease in a specific period
/ Number of people at risk of
developing the disease at the start
of the period
Incidence rate:
Number of people who develop
the disease in a specific period
/ Number of person-years at risk of
developing the disease
Relative risk equations
Rate ratio= IRE / IRC
Risk ratio = IPE / IPC
Risk difference equations
IRE – IRC
IPE - IPC
Historical cohort studies
- Use existing data
- Reconstruct follow-up period in the past
Odds ratios
Measure of association -
Ratio of odds instead of incidences
How many times as likely cases are to have the exposure compared to controls
Interpreting the odds ratio
Interpret the same as the relative risk (in this course)
Randomisation
Randomly assign
participants to
intervention or control
Successful randomisation
means?
confounding is an unlikely
reason for differences in
outcomes between groups
Non
-adherence
Participants don’t do what they’re supposed to
Can include doing what the other group is doing
Clinical Equipoise
is the requirement that researchers only provide an experimental treatment if the evidence for the experimental treatment is equal to that available for the standard treatment
Beneficence
refers to the obligations that we have to ‘benefit’ others. In research it is the obligation to ensure that the research
is generating something of value that justifies the costs
Non-maleficence
the obligation that we have not to
harm others without a justifying reason. In research this means
being aware of the various potential harms to participants and
others, and either taking steps to avoid these or ensuring that
the benefits are sufficient to justify the harms
A vulnerable person
is any person who is more at risk of
exploitation, because of social or physical disadvantages
A conflict of interest
is a situation where a person holds two or more potentially incompatible interests. These are of concern in research where the researcher(s) have interests that might compromise the
values and standards of ethically appropriate research
Informed consent
is ordinarily required when participants are enrolled in research studies
Adequately informed consent requires:
- Disclosure of the purpose, risks, and processes of the study
- Reasonable efforts from the researcher to explain this information
- That the person is competent to give consent
- The absence of any coercive factors (including financial inducements)
Justice requires:
- Transparency
- That all people are considered of equal worth
- That efforts are made to make society equitable
