How Do I Calculate Age-Adjusted Incidence?

Incidence is the measure of new disease in a population over a specific time. Age-adjusted incidence specifically weights the number of persons in a certain age group of the standard population usually to determine the effects of a particular illness or disease. This is a common epidemiological tool that is used in research, prevention and treatment of disease. Age-adjusted incidence is a rate used to make comparisons between groups more fair in terms of comparability between groups.

Things You'll Need

• Data set
• Calculator

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Instructions

• 1

  Write down the total number of cases in the age groups to be studied. This will be known as the age-specific rate. Multiply the number of cases by 100,000 and divide by the estimated population per age group.

• 2

  Weight each of the age-specific rates. Do this by multiplying the number of cases in each age group by the total reference (standard) proportion determined by the data set.

• 3

  Add together each weighted rate across age group. The total is the age-adjusted incidence. Age-adjusted incidence equals the sum of age-specific rates multiplied by the standard proportion.