Health Statistics

Incidence rate- is a measure of disease frequency that describes how fast new cases (incident cases) are developing.

Incidence rate equals: # of new cases ÷ person-time (a quantification of how long individuals at risk of disease are followed up, i.e., person-years)

Morbidity- is another term for illness or adverse outcomes related to a health condition. A person may have several co-morbidities. 

Mortality- is another term for death. 

Annual mortality rate equals: # of deaths due to disease ÷ total population at risk for the disease in a single year.

Prevalence- is a measure of disease frequency that describes the proportion of the population that has an existing disease at a single point in time.

Prevalence equals: total # of cases of disease in a population ÷ total population at risk for the disease.

Risk- is the probability that an event will occur. The risk of disease is also called the cumulative incidence of disease and measures the proportion of a population that acquires disease over a certain time interval.

Study design- involves the formulation of trials and experiments to conduct medical and epidemiological research.

Vital statistics- are statistics on live births, fetal deaths, deaths, marriages, and divorces. This data is publicly available and is commonly collected via civil registration.

When evaluating statistics, you should consider the following:

• Who collected and published this statistical data? Have you located their credentials?
• What are the statistics being reported? What populations does it include?
• Is the information relevant and current enough?
• For what purpose was this information collected? For whom was it intended? 
• What methodology was used to collect the statistics? Are the results scientific in nature?