Spain (1)

Title of the survey

Encuesta de Salarios en la Industria y los Servicios (Survey of Wages in Industry and the Services).

Organization responsible

Instituto Nacional de Estadística (INE).

Periodicity of the survey

Quarterly, on a continuous basis.

Objectives of the survey

To obtain information on the following: average number of hours per worker and month; average earnings per hour; average earnings per worker and month.

Main labour topics covered by the survey

Earnings and hours of work.

Reference period

One month.

Coverage of the survey

Geographical

The whole national territory.

Industrial

Industry, construction, trade, hotels, transport and communication, banks and insurance. A total of 45 branches of economic activity are surveyed. The following are excluded: agriculture, hunting and forestry; real estate and business services; community, social and personal services.

Establishments

Establishments with five or more workers which are centres of contributions to the social security.

Persons

All employees who carry out their activities in these centres.

Occupations

Not relevant.

Concepts and definitions

Employment

An employee is any person bound to a unit of production by a contract of employment, regardless of the type of contract. The following are not regarded as the employees: working proprietors, commission agents, home workers and persons subcontracted from other enterprises, persons temporarily absent from work because of military service, persons not at work during the whole month because of temporary incapacity to work or short-time working, persons under contract for the month and members of the family. Employees are divided into:

persons working a normal day, and
persons working part-time (working 26 hours or less per week, or less than two-thirds of the normal working day).

Each of these is further divided into salaried employee or wage earners. These categories are defined in accordance with the professional classification based on contributions to social security.

a salaried employee is any worker whose contribution group is between 1 and 7, i.e. engineers and graduates, technical engineers, technicians and qualified assistants, administrative chiefs and workshop foremen, unqualified assistants, administrative officials, auxiliaries and administrative assistants; and
a wage earner is any worker whose contribution group is between 8 and 12, i.e. first and second-grade officials, third-grade officials and specialists, non-specialized workers aged 18 years or over and workers under 18 years of age.

Earnings

The remuneration paid to workers, in cash or in kind, for the time worked or for the work performed, together with remuneration for time not worked, such as vacations and holidays. These are gross earnings, i.e. before any deduction for tax or contributions to social security by the worker. Earnings include:

the basic salary and
supplements to salary; these may be:
- personal, e.g. for seniority, qualifications, knowledge of foreign languages or special knowledge,
- for the place of work, for instance supplements for difficulty, danger or toxicity,
- for the quantity or quality of work, such as bonuses and incentive pay, supplements for attendance or activity and overtime,
- supplements falling due at periods longer than one month, such as gratuities, irregular payments, profit-sharing bonuses etc.,
- in kind.

Information is collected separately on the various types of payments:

ordinary payments: these are monthly payments, including payments for overtime paid pro rata,
irregular payments: these are payments falling due at intervals of more than one month and not shared out pro rata (Christmas bonuses, shares in profits),
total payments: this refers to total payments and includes ordinary payments, irregular payments and delayed payments (phasing-out of an agreement).

Wage/salary rates

Not relevant.

Hours of work

These are the hours which form part of the employment relationship between the worker and the employer and the development of the former's activity. A distinction is made between:

agreed hours: the hours laid down in the contract between the worker and the employer. The number of hours agreed upon per month is the average per month of the number of agreed hours per year,
hours actually worked: these are obtained by calculating the difference between the agreed hours and hours not worked because of vacation, temporary incapacity to work, layoff or labour dispute, and adding the hours actually worked in overtime.

Data are separately compiled on earnings and hours of work for full-time and part-time workers and for categories of salaried employees and wage earners. Once a year, data on earnings and hours by sex are surveyed, by means of an additional questionnaire.

International recommendations

The definition of total earnings includes payments falling due at intervals of more than one month, whether paid pro rata or not, and payments in kind. The concept of hours of work corresponds to that of hours actually worked. Both concepts comply with the current international recommendations on statistics of wages and hours actually worked.

Classifications

Industrial

The 1974 Clasificación Nacional de las Actividades Económicas (CNAE) is used and coding is carried out at the three-digit level. The results are published separately by divisions and groupings of branches of economic activity. The CNAE is compatible with the International Standard Industrial Classification of all economic activities (ISIC), Rev. 2, 1968 at the divisions level (two-digit level). Since 1993, ISIC, Rev. 3, 1990, has also been used.

Occupational

Not relevant.

Others

The data are classified by category (salaried employees and wage earners, according to the professional classification based on contributions to social security) and size of establishment. Results are also available at the national level and by autonomous communities.

Sample size and design

Statistical unit

The unit providing the data is the contribution account to social security, which is also the basic unit on the social security records. The unit is made up of a number of workers of one enterprise who pay the same contributions and whose activity is carried out in one province. This group of workers has an employer's registration number for the enterprise inscribed with the social security. Although in theory the establishment and centre of work and contribution account are not identical, in practice both concepts coincide in a considerable percentage of cases.

Survey universe / sample frame

The survey frame is the directory of enterprises obtained from the social security records of contribution accounts. This directory includes the units covered by the survey (centres of contributions with five or more workers). The record of contribution accounts is the only directory available which supplies information, continuously updated, on the workforce, from the point of view of the enterprises. The frame is brought up to date every year in order to record recruitment and discharges of workers in the units in the universe.

Sample design

Stratified sampling is carried out, according to size of contribution centre and branch of activity. Over 9,000 enterprises are selected, using information on the total number of contribution centres and a sampling error of less than five per cent. All establishments with 200 or more employees are included in the sample. The design corresponds to a continuous, quarterly survey, with the sample uniformly distributed over the three months of the quarter. The frame is brought up to date once a year and 20 per cent of the non-exhaustive sample units are renewed, so that in five years the non-exhaustive sample is totally renewed.

Field work

Data collection

The questionnaire is sent by post every month to one-third of the sample, and is also returned by post by the establishment. In addition, all the establishments are visited by the enumerator when they become part of the sample and whenever it is thought appropriate. The postal service is also supplemented by the interviewers recruited for the survey.

Survey questionnaire

This consists of three main sections, covering the following variables:

workers during the reference month:
- payroll at the end of the month, less:
- workers to be excluded according to the definitions supplied,
- workers covered by the survey;
workers on a normal working day, by category:
- number of workers,
- annual agreed hours per worker,
- annual days of leave, per worker,
- number of weeks paid (only for permanent payments),
- total number of days of absence through temporary incapacity for work (ILT),
- total number of overtime hours,
- hours not worked because of lay-off,
- hours not worked because of a labour dispute,
- total basic wages and salaries and supplements. From this total, detailed data concerning: payment for overtime; overtime payments not made pro rata; back payments; payments for ILT; and payments because of lay-off.
Workers with shortened working hours, by category:
- number of workers,
- number of hours per week per worker,
- number of weeks paid (only for weekly payments),
- total number of days of absence through ILT,
- total basic wages and salaries and supplements. From this total, detailed data concerning: payment for overtime not made pro rata; back payments; payments for ILT.

Instructions are sent with the questionnaire and the investigators have an instruction manual.

Substitution of sampling units

The establishments with a reduced number of workers because they have gone out of business are replaced every month by other establishments with the same characteristics.

Data processing and editing

The data are recorded and processed by computer. They are checked for consistency with the data provided by the same establishment in previous periods and against data provided by other establishments with the same characteristics in the event of missing questionnaires, inconsistent data, etc. There is also recourse to consultations by telephone and personal visits.

Types of estimates

Average earnings per hour worked and per worker per month; and average hours per month. In the estimates, part-time workers are converted to their full-time equivalents

Construction of indices

Index numbers of average earnings per hour worked and per worker per month are calculated, for the normal working day and for overtime, with base November-December 1980/January 1981 = 100.

Weighting of sample results

Quotients of simple ratio estimates are used, taking the number of workers at the contribution centre as an auxiliary variable:

F_ij = D'_ij / d'_ij

where,

D'_ij = D_ij (1-d'_ij / d_ij)

F_ij: raising factor for lay-offs in the sample,
D_ij: workers, according to the directory, in the establishments in the directory (branch i, stratum j),
d_ij: workers, according to the directory, in the establishments in the sample (branch i, stratum j),
d'_ij: workers, according to the directory, in the establishments of the actual sample.

Recently, a new sub-index k (= the region) was added.

Adjustments

Non-response

None. Non-response is corrected by imputing data for the missing questionnaires, using the information provided in the previous period.

Other bias

None.

Use of benchmark data

Not relevant.

Seasonal variations

Not relevant.

Indicators of reliability of the estimates

Coverage of the sampling frame

The social security record is continuously brought up to date. The directory is renewed every year. The record is thought to cover about 85 per cent of total employment.

Sampling error / sampling variance

Sampling errors for the concepts earnings and hours of work are calculated; they are less than 2.5 per cent.

Non-response rate

About two per cent in terms of units.

Non-sampling errors

Not available.

Conformity with other sources

Not relevant.

Available series

Average number of hours worked per worker per month, according to type of working day (normal and overtime), by category and branch of activity, division of the CNAE and sector of activity,
Average earnings per hour worked and average earnings per worker per month, according to type of payment (normal and total) and working day, by category, branch of activity and division of the CNAE,
Results by Autonomous Communities.

History of the survey

Since 1963, the Instituto Nacional de Estadística has compiled statistics on wages. Over the years, the statistics have been modified, adapting their objectives to the needs of each moment. The Survey of Wages in Industry and the Services began with the first quarter of 1989, replacing the 1981 Survey of Wages which remained in force until December 1988. The main differences with regard to the previous survey relate to the group of workers, coverage, geographical breakdown, results disaggregate by sex and the simplification of the questionnaire. A connection was established between the 1981 Survey of Wages and the Survey of Wages in Industry and the Services. In 1993, the International Standard Industrial Classification of all economic activities (ISIC) Rev. 3, 1990 was introduced. The design of the questionnaire was modified in 1993, without however affecting the types of information. It is intended to introduce new modifications into the questionnaire in 1996. Owing to the labour reform law adopted in 1994, the definition of part-time worker has been modified: workers who work for less than two-thirds of the normal working day (without lower limit). Previously, the definition referred to persons who worked for a period between one-third and two-thirds of the normal working day. Persons who worked less than one third of the normal working day were excluded.

Documentation

Instituto Nacional de Estadística (INE): Encuesta de Salarios en la Industria y los Servicios (quarterly; Madrid). idem: Boletín Mensual de Estadística (monthly; ibid.). idem: Boletín Trimestral de Coyuntura (quarterly; ibid.). All these publications contain methodological information. For methodological information on the link with the Survey of Wages, see also: idem: Encuesta de Salarios en la Industria y los Servicios (Resultados correspondientes a los tres primeros trimestres del año 1989) (ibid.; 1990). The survey data are also available on diskette.

Confidentiality / Reliability criteria

In accordance with Law No. 12/1989 on the public statistics service, information may not be divulged if the level of classification would permit the respondent to be identified. In concrete terms, if any data are obtained from three questionnaires or fewer, they are not released.

Other information

Data supplied to the ILO for publication

Annual averages of earnings per hour in non-agricultural activities and in particular industries are published in Tables 16 to 20 of the Yearbook of Labour Statistics. Quarterly series of hours per month and of average earnings per hour and per month, in non-agricultural activities and in manufacturing, are also published in the Bulletin of Labour Statistics.