Lecture 6 Flashcards
Lead Time
The interval by which time of diagnosis is advanced by screening and early detection of disease compared with usual time of diagnosis. You have a head start.
Critical Point
Point in natural history before which treatment is more effective/less difficult to administer. This is the ideal stage to administer treatment.
What occurs in the preclinical phase?
- Biologic onset of disease
- Disease detectable by screening
What happens during the Clinical Phase?
- Symptoms first appear
- Disease Diagnosed
- Therapy Given
There may be a benefit to individuals from screening and early detection if
There is a reasonably long DPCP.
Without any intervention, most if not all cases in preclinical phase progress to clinical phase.
The period from the time when symptoms develop…to…cure or control of disease or death is the:
Clinical Phase
What are the three study types?
- Descriptive
- Observational
- Experimental
What do descriptive studies do?
They count and describe outcome (who, when, where, how many?)
Analytic Studies
They analyze factors that may affect outcome.
When is a descriptive study useful and not useful?
They are not useful for establishing causal relationships between an exposure and an outcome.
Useful when describing characteristics of a population and for generating hypotheses.
When is an analytic study helpful?
They are used to identify risk factors for diseases and other conditions and relationships between variables.
How do study designs differ?
They differ by whether the exposure and outcome are measured in past, present, or future.
What is the unit of observation for ecologic studies?
Groups like countries, states, counties, and census tracts
Also known as aggregate data.
What does the ecologic study aim to do?
Assess correlation between exposure rates and disease rates among different groups or populations.
What is another name for an ecologic study design?
Correlation Study
