Age adjustment (exit DHS; PDF, 122 KB) is the application of age-specific rates in a population of interest to a standardized age distribution. It enhances the comparability of populations by controlling for the effects of their differing age compositions. The age-adjusted rate for a population of interest can be compared to that of a different age-adjusted population at the same point in time or the same population at a different point in time. Age-adjusted rates in WISH are calculated using the direct method based on the year 2000 U.S. standard population.
Causes of Death -- Broad Groups:
Underlying causes of death grouped into 50 categories defined by the National Center for Health Statistics. These broad groups condense the more detailed 113 categories by creating more general disease groups and by combining vaguely defined "other," "not elsewhere classified," and "unspecified" causes into an "all other" category.
Causes of Death -- Detailed Groups:
Underlying causes of death grouped into 113 categories by the National Center for Health Statistics. These 113 categories are consolidated from the tenth revision of the International Classification of Diseases (ICD-10) coding structure. They replace the ICD-9 list of 72 selected causes of death used from 1979 through 1998.
The mortality rate is calculated by dividing the number of deaths per year by the population. It is usually expressed as the number of deaths per 100,000 population. The rate may refer to deaths in a specific group, or to deaths from a specific cause, or to all deaths in the entire population. The rate may be adjusted for the age composition of the group (see "age adjustment," above) or it may be the observed (or "crude") rate.
Rates by Race and Ethnicity:
The population estimates used as denominators for the mortality rates in WISH are based on the bridged race estimates (exit DHS) provided by the U.S. Census Bureau and the National Center for Health Statistics (NCHS). The estimates have been controlled so they sum to the annual estimates published by the Office of Health Informatics.
Producing the bridged race estimates was necessary because race categories in Census 2000 differed from those used in previous years. Specifically, data on race from Census 2000 were not directly comparable to data from previous years, due largely to giving respondents the option to report more than one race.
As a result, NCHS and the Census Bureau produce bridged race estimates that allow calculation of rates by race and ethnicity across years. These estimates distribute (or "bridge") the "more than one race" and "some other race" populations into one of four major race groups (American Indian/Alaska Native, Asian/Pacific Islander, Black, and White) and two ethnicity groups (Hispanic/Latino, non-Hispanic/Latino).
NCHS and the Census Bureau have produced this set of bridged race estimates extending back to the 1990 Census, and plan to produce the estimates on an annual basis in the future. WISH will be updated each year as these estimates become available.
Underlying Cause of Death:
The underlying cause of death is defined by the World Health Organization (WHO) as the disease or injury that initiated the train of events leading directly to death, or the circumstances of the accident or violence which produced the fatal injury. Under international rules for selecting underlying cause from the reported conditions, every death is attributed to one underlying cause based on information reported on the death certificate.
Causes for deaths that occurred in 1999 and later have been coded according to the International Classification of Diseases, Tenth Revision (ICD-10). Causes of death were coded using the International Classification of Diseases, Ninth Revision (ICD-9) for deaths occurring in 1979-1998.
Years of Potential Life Lost (YPLL):
An estimate of premature mortality, defined as the number of years of life lost among persons who die before age 75. YPLL is the sum of the differences between age 75 and the age at death for everyone who died before age 75.