Data quality, concepts and methodology

Definitions

The definitions used for the production of statistical tables of Canadian vital statistics data are based on those recommended by the World Health Organization ¹ and the United Nations. ²

Age.  Age attained at the last birthday preceding death. In the case of infant deaths, the completed number of months (or minutes, hours, or days) since birth.

Cause of death. The cause of death coded and tabulated is the underlying cause of death. This is defined as “(a) the disease or injury which initiated the train of morbid events leading directly to death, or (b) the circumstances of the accident or violence which produced the fatal injury”. This underlying cause of death is selected from a number of conditions listed on the medical certificate of cause of death.

Beginning in the year 2000 in Canada, causes of death and stillbirth are coded to the 10th revision of the World Health Organization’s International Statistical Classification of Diseases and Related Health Problems (ICD-10). The previous revision, ICD-9  ³ was used in Canada for the classification of cause of death and stillbirth from 1979 to 1999.

Death.  The permanent disappearance of all evidence of life at any time after a live birth has taken place. Stillbirths are excluded from death statistics unless otherwise indicated.

• Early neonatal death: Death of a child under one week of age (0 to 6 days).
• Infant death: Death of a child under one year of age.
• Neonatal death: Death of a child under four weeks of age (0 to 27 days).
• Perinatal death: Death of a child under one week of age (0 to 6 days) or a stillbirth of 28 or more weeks of gestation.
• Post-neonatal death: Death of a child under one year of age but at least 28 days old (28 to 364 days).

Death rates

• Age-standardized death rate: Age-standardization removes the effects of differences in the age structure of populations among areas and over time. Age-standardized death rates show the number of deaths per 100,000 population that would have occurred in a given area if the age structure of the population of that area was the same as the age structure of a specified standard population.

• Age-specific death rate: The number of deaths in a particular age group during a given year per 100,000 population in the same age group as of July 1 of the same year.
• Crude death rate: The number of deaths during a given year per 1,000 population as of July 1 of the same year.
• Early neonatal death rate: The number of early neonatal deaths during a given year per 1,000 live births in the same year.
• Infant death rate: The number of infant deaths during a given year per 1,000 live births in the same year.
• Neonatal death rate: The number of neonatal deaths during a given year per 1,000 live births in the same year.
• Perinatal death rate: The number of perinatal deaths during a given year per 1,000 total births (live births plus stillbirths of 28 or more weeks of gestation) in the same year.
• Post-neonatal death rate: The number of post-neonatal deaths during a given year per 1,000 live births in the same year.

Delivery. A delivery may consist of one or more live born or stillborn fetuses. The number of deliveries in a given period will be equal to or less than the total number of births because a multiple birth (twins, triplets or higher-order multiple births) is counted as a single delivery.

Gestational age. The interval, in completed weeks, between the first day of the mother’s last menstrual period and the day of delivery (that is, the duration of pregnancy). It can also be an estimate of that interval, based on ultrasound, a physical examination, or other method. Canadian birth registration documents do not specify how the gestational age was calculated. Pre-term refers to a period of gestation under 37 completed weeks; term, 37 through 41 completed weeks; and post-term, 42 or more completed weeks.

ICD-10 codes. The International Statistical Classification of Diseases and Related Health Problems (ICD) codes, 10th Revision, were established by the World Health Organization in 1992. The ICD-10 manual assigns codes to specific diseases, injuries and causes of death.

Life expectancy. The average number of remaining years of life, at birth or other age, based on the set of age-specific mortality rates calculated for a given year.

Live birth. The complete expulsion or extraction from its mother of a product of conception which, regardless of the duration of pregnancy, subsequently breathes or shows any other evidence of life.

Marital status. The legal conjugal status of the deceased at the time of death. Persons in common-law relationships are categorized by their legal marital status. A single person is one who has never been married, or a person whose marriage has been annulled and who has not remarried. A separated person is legally married but is not living with his or her spouse because the couple no longer wants to live together. A divorced person is one who has obtained a legal divorce and has not remarried. A married person is one who is legally married and not separated. A person whose spouse has died and who has not remarried is widowed.

Population. Persons whose usual place of residence is somewhere in Canada, including Canadian government employees stationed abroad and their families, members of the Canadian Armed Forces stationed abroad and their families, crews of Canadian merchant vessels, and non-permanent residents of Canada.

Adjusted population estimates are used in vital statistics to better reflect Canada’s population; these estimates include upward adjustments for net census under-coverage and non-permanent residents. Net census under-coverage is the difference between census under-coverage and census over-coverage. The former refers to persons who were part of the census universe, but were not enumerated in the census; the latter, to persons either enumerated more than once, or enumerated but not part of the census universe. Non-permanent residents are persons claiming refugee status, persons holding student or employment authorizations, or a Minister’s permit, and all non-Canadian-born dependents of the above individuals.

Mid-year (July 1) population estimates are used to calculate the rates in vital statistics publications. Population estimates are revised frequently by Statistics Canada’s Demography Division.

The standard population used in the calculation of age-standardized death rates is the 1991 Canadian Census of Population, by age group, both sexes together.

Provinces and territories. Unless otherwise stated, the geographic distribution of deaths in the tables of this publication is based on the deceased’s usual place of residence.

Nunavut came into being officially as a Territory of Canada on April 1, 1999. The name Northwest Territories applies to a Territory with different geographic boundaries before and after April 1, 1999.

Deaths and stillbirths of residents of Nunavut which took place before April 1, 1999 are included with deaths and stillbirths of residents of the Northwest Territories. Deaths and stillbirths which took place on or after April 1, 1999 are tabulated separately for residents of Nunavut.

Stillbirth. The complete expulsion or extraction from its mother of a product of conception, which did not at any time after birth breathe or show any other sign of life.

Most provinces and the three territories require a stillbirth with a gestational age of at least 20 weeks or a birth weight of at least 500 grams to be registered. In Quebec and Saskatchewan (and New Brunswick, prior to November 1996), only stillbirths weighing 500 or more grams must be registered, regardless of the gestational period. Until 1997, only stillbirths with gestational periods of at least 20 weeks were required to be registered in Prince Edward Island, regardless of birth weight.

Stillbirth data are tabulated according to the mother’s place of residence.

Stillbirth rate. The number of stillbirths per 1,000 total births (live births plus stillbirths).