An<unk>  (or incident rate) is the probability or risk of an<unk>  in a population. It is used to measure the frequency of occurrence of new instances of<unk>  within a population during a specific time period. The number of<unk> s equals the cases identified in the study or observed. An example would be HIV<unk>  during a specific time period in the defined population. The population at risk are the cases appearing in the population during the same time period. An example would be all the people in a city during a specific time period. The constant, or K is assigned a value of 100 to represent a percentage. An example would be to find the percentage of people in a city who are infected with HIV: 6,000 cases in March divided by the population of a city (one million) multiplied by the constant (K) would give an<unk>  of 0.6%. Calculating the<unk>  is used to analyze trends for the purpose of<unk>  and disease control. An online<unk>  calculator has been developed by the Centers for Disease Control and Prevention that allows the determination of the Streptococcal A<unk>  in a population.
Infection rate
Mortality rate
Risk of mortality
Case fatality rate
Survival rate
Apparent infection rate
Prevalence
Transmission risks and rates