Standard set of criteria for determining whether a person has the disease or health outcome of interest.

construction can include physical signs

Symptoms

results of lab tests

*usually time bounded as to occurrance 

Host: intrinsic and/or extrinsic charac teristics

Environment: macro and/or micro level

Agent: biologic, chemical, physical, etc

Vector 

The proportion of susceptibles that acquire infection upon exposure over a specific time frame=

=number w/risk and disease/number at risk 

the mixing of the effect of the pirimary exposure of interest upon the disease with the effect of a second factor

This second factor is related to botht he primary exposure and the disease 

proportion of persons with disease that die of that diesase within a specific time frame.

For use in cohort studies

a/(a+b)/c/(c+d) 

For use with case control studies

a*d/b*c 

[a/(a+b)]-[c/(c+d)]

absolute measure of the effect of exposure, compared to non-exposure; the excess occurence of disease in the study sample due to risk factor. 

• privacy and confidentiality
• voluntary participation
• informed consent must be obtained
• informing subjects of results of study

• balance of doubt and belief regarding product or procedure to be evaluated
• cannot knowingly instigate harm, only modify its removal
• anticipate unintended effects
• stopping rules

1st step to understanding a population

• provide basic info for allocation of health resources for prevention and care
• provide the initial inof base for hypothesis generationf and analytic study design parameters 

• ecologic
• correlation
• case reports or series
• cross-sectional

• examines information at the aggregated populatin level
• the difference between populations can be described but the etiology of disease cannot be established

• diesase data
  • disease incidence rates, disease prevalence or cause-specific mortality rates