This volume of Sources and Methods: Labour statistics presents methodological descriptions of the national statistics of:

• employment, wages and hours of work, and
• labour cost or compensation of employees,

which are derived from establishment surveys generally conducted each month or quarter, half-yearly or annually, etc. The corresponding statistical series are published by the ILO in the 1995 edition of the Yearbook of Labour Statistics and, where relevant, in the quarterly Bulletin of Labour Statistics or its Special supplement Statistics on occupational wages and hours of work and on food prices: October Inquiry results. This volume has two main purposes:

• to provide basic information on the sources and methods used in each country in compiling the statistics which are published by the ILO, so as to enhance the usefulness of these data for different purposes; and
• to indicate the differences between the national series with regard to their coverage, definitions, methods of measurement, methods of data collection, reference periods, etc.

The descriptions presented here refer to establishment or enterprise surveys, industrial or commercial surveys or censuses, or specially-designed labour cost surveys, etc. In a few cases, the statistics of labour cost or compensation of employees are official estimates. A synoptic table presents the essential features of the current versions of these surveys or estimates. Where several descriptions are published for one country, the surveys are identified by a serial number. Extracts from the ILO resolutions on statistics of wages, hours of work and labour cost are shown in the Annex. The definition of compensation of employees appears in the System of National Accounts (SNA). The descriptions presented in this volume cover 71 countries and 127 surveys. They were prepared on the basis of information provided by national statistical agencies or governments in response to two specially designed questionnaires, one for statistics of employment, hours of work and wages, and the second for statistics of labour cost or compensation of employees. In some cases, the information was collected from national publications. Each description was submitted to the country concerned for comments, which were taken into account if received within the limits of the publication programme. Countries for which series are published in the ILO Yearbook of Labour Statistics and/or Bulletin of Labour Statistics, but for which methodological information was not complete enough by July 1995 to be included in this publication, are listed at the end of the table of contents. The descriptions are structured and presented using standard sections and headings in order to facilitate comparisons. The heading of the descriptions related to statistics of labour cost or compensation of employees are not all the same as those relating to the statistics of employment, wages and hours of work. However, the format has been kept as similar as the treatment of the two subjects permits. The respective headings and their contents are described below:

Title of the survey

The title of the survey is given in the original language or in the language used in official correspondence between the country and the ILO, with, if necessary, its English translation.

Organization responsible

This heading refers to the organization responsible for data collection, statistical processing and publication of the results. Where these functions are undertaken by separate agencies, each of them is specified.

Periodicity of the survey

This heading refers to the frequency with which the survey is conducted (e.g. monthly, quarterly, half-yearly, once a year).

Objectives of the survey

The main objectives of the survey and the major uses of the results, as stated by the countries, are given there.

Main labour topics covered by the survey

This refers to the main labour topics for which data are collected in the survey (i.e. employment, earnings, wage or salary rates, hours of work, labour cost, compensation of employees, vacancies, labour turnover, etc.). In the case of industrial surveys or censuses, industrial data such as output, value added, sales, etc. are not usually mentioned.

Reference period

This heading gives the time period (e.g. a specific week, a full month, the last pay period, a specific date or a year) for which data are collected. The reference period may differ for each labour topic.

Coverage of the survey

Geographical

This indicates whether the survey covers the whole country or territory and, in cases where the coverage is limited, the relevant cities, areas or regions which are included or excluded.

Industrial

This indicates the economic activities covered by the survey, and, in cases where the coverage is limited, which groups of industries or activities are included or excluded.

Establishments

Information is provided on the type of establishments covered by the survey (e.g. all types and sizes of establishments or enterprises, those above a specified size of employment or volume of production, those with a certain type of ownership such as public or private).

Persons

This indicates the categories of workers covered, such as all persons employed, all employees, wage earners only, and the population groups which are excluded, if any (e.g. self-employed persons, unpaid family workers, foreigners, expatriate workers).

Occupations

This indicates whether the data are collected by occupation or occupational group and, if so, which occupations or occupational groups are covered. It should be noted that in general, labour cost and industrial surveys or censuses do not collect data by occupation or occupational group.

Concepts and definitions

Employment

The national definitions of the categories of workers covered and separately identified are provided here, (e.g. persons engaged, employees, wage earners or salaried employees, full-time and part-time workers) and information is given on the types of workers included and excluded. In addition, this heading indicates whether the workers are identified according to specific characteristics (e.g. sex, citizenship, skill level).

Earnings

Information is provided on the national definition and components of earnings used in the survey, whether they refer to gross or net earnings, and whether the components are separately identified. This heading also indicates whether the earnings data cover the same categories of employees as the employment data, and if not, which categories are excluded (e.g. part-time workers, young workers). Where relevant, the different categories of employees for whom earnings data are collected separately (e.g. nationals and foreigners, full- and part-time workers, by sex or skill level) are indicated.

Wage/salary rates

Where relevant, this indicates the national definition and components of wage or salary rates, and whether they refer to minimum rates, average rates actually paid, time rates or piece rates. This heading also indicates whether the data cover the same categories of workers as the employment data and, if not, which categories are excluded (e.g. part-time workers, young workers). The different categories of employees for whom wage or salary rates are collected separately (e.g. nationals and foreigners, full- and part-time workers, by sex, skill level) are indicated.

Hours of work

This indicates whether the survey covers hours or time actually worked, hours or time paid for, normal hours of work or some other concept, and provides the definition and the components of hours of work. It also indicates whether the data cover the same categories of workers as the employment and wages data and, if not, which categories are excluded (e.g. part-time workers, young workers). The different categories of employees for whom data on hours of work are collected separately are indicated.

Labour cost

This heading provides information on: the national definition of labour cost and its components; the detailed components which are separately identified; the categories of employees covered by the data, those that are excluded, and the various categories for whom labour cost data are collected separately (e.g. wage earners and salaried employees).

Compensation of employees

Where relevant, this heading provides information on: the national definition of compensation of employees and its components; the detailed components which are separately identified; the categories of workers covered by the data, those that are excluded, and the various categories for whom data are collected separately (e.g. all persons engaged, employees).

International recommendations

Under this heading, a short statement indicates whether the national definitions of earnings, wage rates and hours of work, where relevant, conform to, or differ from, the concepts and definitions contained in the current international standards and guidelines on labour statistics, and in particular, the ILO Resolution concerning an integrated system of wages statistics (12th International Conference of Labour Statisticians - ICLS, 1973), and the Resolution concerning statistics of hours of work (10th ICLS, 1962). Where relevant, it indicates whether the national definition of earnings complies with that of wages and salaries contained in the System of National Accounts. In the descriptions of labour cost statistics, it indicates whether the definition of labour cost conforms to, or differs from, the concept and definition contained in the ILO Resolution concerning statistics of labour cost (11th ICLS, 1966). Where relevant, it provides an indication of whether the national definition of compensation of employees complies with the concept and definition contained in the System of National Accounts.

Classifications

Industrial

This indicates the name of the national industrial classification used, and whenever possible, the number of groups that are used for coding the data; whether this classification applies to all the data collected; and whether the national classification is linked to the International Standard Industrial Classification of all economic activities (ISIC), either Rev.2 (1968), or Rev.3 (1990).

Occupational

This indicates the name of the national occupational classification used, and whenever possible, the number of groups that are used for coding the data; whether this classification applies to all the data collected; and whether the national classification is linked to the International Standard Classification of Occupations (ISCO-1968 or ISCO-1988). CCOM This indicates the groups of components used to classify the statistics, and whether the classification is linked to the International Standard Classification of Labour Cost (ISCLC-1966).

Others

Information is provided on the other classifications used, such as establishments' characteristics (size, type of ownership, etc.), region, workers' characteristics (sex, age groups, employee categories, skill levels, citizenship, etc.); and whether these classifications apply to all the data collected or to some of them only.

Sample size and design

This section applies when the statistics are derived from an establishment survey or census.

Statistical unit

This heading provides the definition of the sampling unit (e.g. establishment, enterprise, local unit), and that of the reporting unit or unit of observation, if it differs from the sampling unit.

Survey universe / sample frame

This heading describes the universe or sample frame of the survey (business directory, social security records, industrial census, etc.) and indicates its size and coverage in terms of the number of units and employment, the methods used to update the frame and the frequency of updating.

Sample design

This indicates whether the survey is based on a complete enumeration of all units within the scope of the survey, or whether sampling is used. In the latter case, information is provided on the selection scheme, the stratification and its relevant variables, the sample size and/or sampling fraction, whether rotation sampling is used and the rotation pattern.

Field work

Data collection

This refers to the period and duration of data collection, methods of data collection (by mailed questionnaire, personal interview, computer-assisted interview, combined methods, etc.) and, where possible, provides information on the nature of field staff (whether they belong to a permanent survey organization or are specially-recruited enumerators, etc.).

Survey questionnaire

This provides a short description of the questionnaire used for the survey, and the type of written instructions and manuals made available to field staff and/or respondents.

Substitution of sampling units

This indicates whether sampling units which fail to respond (because they have gone out of business, changed address, refused to respond, etc.) are replaced and, if so, the procedure used.

Data processing and editing

This section describes how the data are processed (manually, by computer, etc.), whether the survey responses are coded and, if so, how the coding is done and verified, the editing procedure (e.g. through field work or machine edit), etc. It also indicates the types of follow-up that are made in the case of non-response and missing or inconsistent data (e.g. contacts by telephone, mail, enumerator's visit), and the range and consistency checks which are made.

Source of the estimates

Where the statistics are in the form of official estimates, this section provides information on the sources which provide the basic data used for computing the estimates (e.g. the results of a survey of earnings or an industrial census).

Types of estimates

Information is provided here on the types of estimates that are made (e.g. totals, averages, medians, deciles, distributions), the time units to which they refer and the method of computation; this section also indicates whether specific adjustments are made (e.g. to take part-time workers into account or to impute missing data). ESTM Where the statistics are in the form of estimates, this heading provides information on the models followed to compute them and, where relevant, on the adjustments made to the basic data.

Construction of indices

Where index numbers are constructed from the survey data, this section indicates the type of data they refer to, the procedure used and whenever possible, the source of the weights.

Weighting of sample results

When sampling is used, the method and formulae used to expand the sample results to the level of the universe are described here.

Adjustments

Non-response

This refers to the adjustments made for bias due to total non-response, and where relevant, describes the procedure.

Other bias

This refers to the adjustments made for other bias such as non-representativeness of the sample, changes in industrial classification, etc. and, where relevant, describes the procedure.

Use of benchmark data

This indicates whether the survey data are realigned against independent estimates (benchmark data), the types of series that are adjusted and the procedure used. OTSV If the results of other surveys (survey of hours of work, employment survey, etc.) are used to prepare statistics of labour cost, the procedure is described here.

Seasonal variations

This indicates whether the survey results are corrected for seasonal variations and, if so, the procedure that is followed.

Indicators of reliability of the estimates

This section provides both qualitative and quantitative information on the reliability of the statistics.

Coverage of the sampling frame

Information is provided here on the proportion of the target population, in terms of units (establishments or enterprises) or employment (number of persons engaged, number of employees, etc.), that is covered by the sampling frame or universe of the survey. This information is related to the nature, size and updating of the frame, as described under Survey universe/sample frame.

Sampling error / sampling variance

If the standard error of estimates is calculated, the typical or latest available standard error is indicated here, for each concept. Information is also provided on the computation of the sampling variance, where relevant.

Non-response rate

The typical or latest rate of non-response, in terms of units and/or employment, is indicated here.

Non-sampling errors

A brief description of any additional sources of bias or errors in the survey results appears under this heading.

Conformity with other sources

Where relevant, an indication of the procedure used to check the reliability of the survey results against other independent sources (other surveys, administrative records, etc.) is provided here.

Estimates for non-survey years

This heading applies to statistics of labour cost which are computed from surveys not carried out each year (for instance, within the European Community). It indicates whether estimates are calculated for non-survey years, and the procedure which is followed.

Available series

This section refers to the main tabulations which are regularly prepared by the country on the basis of the present survey, and which appear in national publications.

History of the survey

This section provides information on the historical background of the survey: the date of the start, the date and nature of major changes and revisions that have occurred (e.g. in sample design, questionnaire design, periodicity, definitions, coverage, classifications) and, where relevant, the changes that are envisaged for the next two to three years.

Documentation

This section provides the source and title of major national publications in which the statistical series appear. It also indicates the periodicity of the publications, and the normal delay between the reference period of the survey and the release of results. In addition, it indicates whether data which do not appear in national publications can be made available upon request, and whether the survey results are available in machine-readable form (diskette, magnetic tape, etc.). Where possible, references to national publications providing methodological details are also included.

Confidentiality / Reliability criteria

Under this heading, information is provided on (i) the confidentiality rules and regulations which govern data collection and publication of the survey results, and (ii) the standards of accuracy and reliability adopted by the responsible agency, which may prevent the disclosure of data.

Other information

Data supplied to the ILO for publication

This section indicates the types of data supplied to the ILO for publication in the Yearbook of Labour Statistics and the Bulletin of Labour Statistics. The tables are identified by chapter and number, and refer to the 1995 edition of the Yearbook and Bulletin. Occasional reference is made to previous editions of these publications.

Other sources of data

Occasional reference is made to other surveys which either provide data published in some of the tables of the Yearbook, or complement the source described in this publication. Generally, detailed information on these additional sources of data was not available at the time of publication. However, a brief description provides basic information on the title, periodicity and coverage of these sources.