Study Set Content:
Measures are ratio, proportions, and rates.
Common frequency
Is the relative magnitude of 2 quantities or a comparison of any two values. It is calculated by dividing one interval-or ratio-scale variable by the other.
Ratio
The numerator and denominator need not be
related
It is a type of ratio in which the numerator is included in the denominator
Proportion
are common descriptive measures, used in all fields, in epidemiology, () are used as both descriptive measures and as analytic tools
Ratios
is a measure of the frequency with which an event occurs in a defined population over a specified period of time. Because () put disease frequency in the perspective of the size of the population, rates are particularly useful for comparing disease frequency in different locations, at different times, or among different groups of persons with potentially different sized populations; that is, a() is a measure of risk.
rates, rate
is the proportion of deaths in a specified population during a period of time that are attributable to differentncauses. Each cause is expressed as a percentage of all deaths, and the sum of the causes adds up to 100%
Proportionate mortality
measures track the occurrence of disease, disability, or injury in a population
Morbidity frequency
refers to the occurrence of new cases of disease or injury in a population over a specified period of time. Although some epidemiologists use incidence to mean the number of new cases in a community, others use incidence to mean the number of new cases per unit of population.
Incidence
is the proportion of an initially disease-free population that develops disease, becomes injured, or dies during a specified period of time. Synonyms include attack rate, risk, probability of getting disease, and cumulative incidence.
Incidence proportion
is a measure of incidence that incorporates time directly into the denominator. The denominator is the sum of the time each person was observed, totaled for all persons. This denominator represents the total time the population was at risk of and being watched for disease. Thus, the () is the ratio of the number of cases to the total time the population is at risk of disease.
incidence rate
e, is the proportion of persons in a population who have a particular disease or attribute at a specified point in time or over a specified period of time. Prevalence differs from incidence in that prevalence includes all cases, both new and preexisting, in the population at the specified time, whereas incidence is limited to new cases only
Prevalence, prevalance rate
refers to the prevalence measured at a particular point in time. It is the proportion of persons with a particular disease or attribute on a particular date.
Point prevalence
refers to prevalence measured over an interval of time. It is the proportion of persons with a particular disease or attribute at any time during the interval.
Period prevalence
measures track the number of deaths due to a particular disease or health condition within a population.
Mortality Frequency
is the mortality rate from all causes ofdeath for a population. In the United States in 2003, a total of2,419,921 deaths occurred. The estimated population was290,809,777. The crude mortality rate in 2003 was, therefore,(2,419,921 / 290,809,777) x 100,000, or 832.1 deaths per 100,000population.
crude mortality rate
is the mortality rate from a specified cause for a population. The numerator is the number of deaths attributed to a specific cause. The denominator remains the size of the population at the midpoint of the time period. The fraction is usually expressed per 100,000 population. In the UnitedStates in 2003, a total of 108,256 deaths were attributed to accidents (unintentional injuries), yielding a cause-specific mortality rate of 37.2 per 100,000 population.
Cause-specific mortality rate
is a mortality rate limited to a particular age group. The numerator is the number of deaths in that age group; the denominator is the number of persons in that age group in the population. In the United States in 2003, a total of 130,761 deaths occurred among persons aged 25-44 years, or an age-specific mortality rate of 153.0 per 100,000 25–44 year olds.
Age-specific mortality rate
s really a ratio used to measure mortality associated with pregnancy. The numerator is the number of deaths during a given time period among women while pregnant or within 42 days of termination of pregnancy, irrespective of the duration and the site of the pregnancy, from any cause related to or aggravated by the pregnancy or its management, but not from accidental or incidental causes. The denominator is the number of live births reported during the same time period. () is usually expressed per 100,000 live births. In 2003, the U.S. maternal mortality rate was 8.9 per 100,000 live birth
Maternal mortality rate
is a mortality rate among either malesor females. Both numerator and denominator are limited to the onesex.
Sex-specific mortality rate
