INEbase / Vital Statistics (VS) / Methodology

Summary
General Methodology. (File PDF 78 Kb.)

Summary

Vital Statistics, which basically refer to births, marriages and deaths in Spain, constitute one of the oldest of the National Institute of Statistics. The first volume was published in 1863 by the KingdomŽs General Statistics Board. It contained data covering the period from 1858 to 1861, obtained from parish registers. From then on information on demographic phenomena has been published in Spain without interruption from 1871 to 1885. This was when the Civil Register was implemented, from which successive data was obtained for these statistics.

Currently statistics are elaborated in collaboration with Autonomous Communities. The main information sources are the Civil Registers. Monthly bulletins on births, marriages and deaths are sent to INE delegations. Each of these bulletins covers the information that refers to just one demographic fact.

Data is recorded at the delegations and transmitted to the INE Central Services.

Either all monthly files with the three statistics or just deaths and live births who died during the first 24 hours of life are also sent to the corresponding Autonomous Community from the delegations, depending on the type of agreement the Autonomous Community in question has signed with the INE.

Concepts

The demographic concepts used for the elaboration of these publications were practically the same every year without variations other than those originating from the change in information source, that fundamentally consists of the replacement of those baptised for those registered in the Civil Register and common law marriage for civil marriage.

Bearing in mind that for civil purposes "the fetus will only be considered born if it has a human figure and lives for twenty four hours completely separate from the womb." (art. 30 civil code). The statistics on births and deaths carried out until 1975 were not adjusted to the demographic concepts recognised internationally, as these do not include those born alive who died before 24 hours of existence, which in the Civil Code, are called "aborted babies" (art 745).

Although the use of this concept does not significantly alter the global figures on births and deaths it considerably modifies some specific mortality rates (infantile, neonatal, perinatal, etc.) To deal with this it is necessary to remove from the so called Abortions Statistic those born alive to calculate the "rectified rates".

Since 1975 the birth concept in the Natural Movement of Population is identified by the biological "born alive" which is that used in the demographic field with the corresponding effect on deaths.

From the theoretical point of view late fetal death is death before complete expulsion or extraction from the body of the mother of a product of viable conception. This character of viability is specifically which serves to differentiate ate fetal deaths from abortions. Traditionally the World Health Organisation (WHO) has identified the viability of the fetus with a gestational age of more than 28 complete weeks of pregnancy. Nevertheless, currently the WHO recommends the use of the criterion of weight when the fetus is expelled or extracted. although the number of grams which must be considered the limit for it to be viable is subject to debate.

Bearing in mind this lack of international uniformity as to weight, the difficulty in obtaining exact weights from all fetuses at the time of expulsion and especially, that in Spain, there only exists an obligation to communicate to the Civil Register fetal deaths of more than 180 days of gestation (art. 45 of the Law from 8 June 1957), the criterion of considering - for the purposes of this statistic - the dead fetus of six or more months of gestation, has been adopted.

The definition of birth coincides with the biological medical concept. In other words, expulsion or extraction from the womb of a product of viable conception; therefore abortion or expulsion of the non viable fetus is excluded.

The concept of marriageis the legal. In other words that registered in the Civil Register.

As can be understood from that expressed above in dealing with statistics on births and late fetal deaths, the statistical concept of deaths used traditionally in Spain included all those deaths with more than 24 hours of life. From 1975 this concept has been broadened with the incorporation of those born alive who died during the first 24 hours. This change is of great importance because it supposes the adoption of the death criterion recommended by International Organisations.

The institute publishes provisional data six months from ending the information reference year and the definitive data after a year and a half from the said reference period. The latter are based on annual files received from Autonomous Communities. These are made up from the INE monthly bulletins after having cleaned them and coded the causes of death.

The definitive data consists of a national volume and 18 Autonomous Community volumes (the latter are only available in electronic publication).