National Health Survey 2003. Methodology

Compared with health objective indicators provided by the mortality study, the perception of health, obtained from individual impressions, provides an essential element for the measurement of health. The perception of each individual reflects the contribution of different factors, social, environmental and lifestyles that go well beyond the health system.

The framework of health strategies that are carried out in our country, whose objective is to improve the population's health, requires this type of subjective information as another essential element for the planning and adoption of public health measures.

The National Health Survey 2003 (NHS) is an investigation on the state of health and determinant factors from citizens' perspective; in other words it offers the vision that people have of their state of health and primary and specialised health care. It provides information on aspects such as perceived mortality, life habits, the conducts related to risk factors, the use of health services and preventive practices. It also facilitates completing the health information system by contributing data from people who do not make use of the health services.

The NHS is a statistical operation included in the National Statistical Plan promoted by the Ministry of Health and Consumption. By virtue of the Framework collaboration agreement between this Ministry and the National Statistical Institute to carry out this survey, signed on 11 March 2002, the INE will subsequently be responsible for the execution of the technical project, the sample design, the preparation of the questionnaires, interviewer training, collection of data and computerised treatment until the final survey files are obtained. The periodicity of the NHS is biannual.

The information referred to doctors and graduates in nursing is collected by means of the professional colleges by the provincial INE delegations.

The National Health Survey 2003 has the general objective of providing the necessary information on the health of the population in order to be able to plan and evaluate health action and provide the appropriate care to health service users.

- General state of health, chronic diseases, pains, discomforts, limitations as they are lived and expressed by citizens. This involves measuring the incidence of each one of these shortcomings or health limitations and their repercussion on people's lives.
- Similarly it involves measuring the repercussion and importance of any type of accident suffered by the population surveyed: where it occurred, effects produced and type of medical consultation caused.
- With respect to the physical characteristics of the population measuring their degree of sensory function is sought, specifically sight and hearing, as well as other physical characteristics such as weight, size and the relationship between the two.
- Finally, buccodental conditions are investigated

- Medical query, with the details of place, reason, specialty, distance or journey, waiting time and type of care received.
- Hospitalisations detailing frequency, duration, type of care or treatment, form of admission, paying institution and where necessary, waiting list.
- Use of emergency services with detail of type and frequency.
- Vaccination against flu with specification of the motivating agent.
- Consulting habits and gynaecological care in women over 16.

- Consumption of alcoholic beverages detailing frequency, quantity consumed by type of beverage (persons 16 and over).
- Consumption of tobacco detailing the frequency, modality of consumption, quantity and history of tobacco consumption habit (persons 16 and over).
- Daily hours of sleep.
- Physical activity required by the main activity and the one carried out in free time.
- Nutrition habits.

- Type of lactancy in the first weeks and months of life
- Knowledge of determined vaccines.
- Time used to watch TV

Once the components of the health concept that will be investigated are determined and the criteria established for which variables are of interest to study, it has been planned to carry out the survey in two phases. The first phase is identified with the household questionnaire and the second with the adults questionnaire (persons 16 and over) and the minors questionnaire (persons 0-15).

In the first phase it is sought to capture all persons resident in the household, requesting information from all members on certain socio-demographic variables. They are also asked on who deals with childcare and housework.

In the second phase information is collected from just one person 16 and over, selected randomly within the household, by means of the adults questionnaire. Data from a minor (0-15) )is also collected, selected randomly from those within the household, by means of the minors questionnaire. A battery of questions referring to the subjects object of study is carried out on these persons: Measure of the use of health and social services, auto evaluation of the state of health, anthropometric characteristics, temporal limitations of daily activities, life habits, accidents, prevalence of chronic diseases, preventive practices and nutrition habits.

The research covers the set of persons that reside in main family households. When the same dwelling is made up by two or more households, the study is extended to all these, but independently for each household.

The collection of information will be carried out over the year, from April 2003 to March 2004.

The type of sample used is a stratified multi stage sample. The first stage units are the census sections. The second stage units are the main family dwellings, investigating all households who have their habitual residence there. Within each household an adult is selected (16 or over) to fill in the adults questionnaire and in the case of their being minors (0-15) a minor is similarly selected to fill in the minors questionnaire. For the sample selectin a framework of areas made up of the list of census sections is used. For the second stage units the list of main family dwellings in each one of the sections selected for the sample has been used.

The stratification criteria used was the size of municipality to which the section belongs.

For each Autonomous Community an independent sample that represents it is designed, due to one of the objectives of the survey being to facilitate data.

To cover the objectives of the survey to be able to facilitate estimates with a certain degree of reliability on a national and Autonomous Community level, a sample of approximately 22.000 dwellings distributed into 1844 census sections has been selected.

The sample is distributed between Autonomous Communities assigning a portion uniformly and another in proportion to the size of the Community.

The information collection method will be personal interview that may be complemented when necessary and in exceptional cases via telephone interview.

It is foreseen that national quarterly results will be obtained that will provide statistical tables for the main individual questionnaire sections (adults and minors questionnaires). These will be carried out on electronic format with the habitual INE software and will be disseminated via the INE web page.

They will provide statistical tables that cover the different sections investigated in the questionnaires. Autonomous tables will be included. Its dissemination will be carried out on paper format and electronic publication and will be incorporated into the INE web tabulation.

The final microdata files will be the basis for dealing with information requests that demand specific and detailed uses. The content of these files will adjust to that established in the Public Statistical Function Law, in agreement with individual data confidentiality and INE microdata dissemination regulations.

INEbase / National Health Survey 2003 / Methodology