Mexico (1)

Title of the survey

Encuesta Industrial Mensual (Monthly Industrial Survey)

Organization responsible

Instituto Nacional de Estadística, Geografía e Informatica (INEGI).

Periodicity of the survey

Monthly.

Objectives of the survey

To obtain reliable and appropriate basic statistical information on manufacturing and on economic trends in manufacturing, which will serve as an indicator of the state of the economy.

Main labour topics covered by the survey

Employment, earnings, hours of work and compensation of employees.

Reference period

The month.

Coverage of the survey

Geographical

The whole country.

Industrial

129 classes of activity in manufacturing are covered.

Establishments

Large establishments which important in terms of total gross output.

Persons

All employees (called employed persons in national publications). Persons who performed professional services for the establishment exclusively for a fee, commission, etc., but who are not part of the workforce of the establishment, are excluded. Home workers who do not appear on the payroll of the establishment and unpaid family workers are also excluded.

Occupations

Information is not collected by occupation.

Concepts and definitions

Employment

Employed persons (i.e. employees) include both permanent and casual workers, persons on sick leave, paid vacation and temporary leave of absence with or without pay. Excluded are persons on indefinite leave or in retirement and workers subcontracted from other enterprises. Employees are divided into:

manual workers: persons who perform tasks mainly manual in nature and directly linked to the operation of machinery and tools (manufacture, assembly and supervision - foremen). They include other workers with tasks related to the production process, such as cleaning, maintenance, repair, dispatch and storage, packing, supply of raw materials, transport, etc., on any shift in which they perform their work;
non-manual workers: persons occupied in management, planning, technical or administrative supervision, in accountancy, records, development of sales, publicity, supervision or security or general office work, and in general all persons who cannot be regarded as manual workers. Administrative employees are excluded when the general offices are outside the production area, i.e. in another management area.

Compensation of employees

These consist of all wages, salaries and social benefits. The following components are identified separately:

wages paid to manual workers;
salaries paid to non-manual workers; Wages and salaries cover all cash payments made during the month to pay for the work performed by workers. They include payments for overtime, bonuses, incentive pay, payment for vacations or temporary leave of absence, and commissions paid to workers (except commission paid to salespersons who receive no wage but simply commission). These are gross concepts, i.e. before any deduction for income tax, social security contributions, etc.
social benefits for employees: benefits which workers receive in addition to their wages and salaries, in cash, in services or in kind. They include medical services, medicines, food, day nurseries, housing, sports grants, other social services, year-end bonuses, employers' contributions to the social security institute of Mexico (IMSS), to the national fund institute for workers' housing (INFONOVIT) and the system of savings for retirement (SAR), payments for unavoidable dismissal and compensation for occupational risks, and all contributions which workers must pay and which are covered at the employer's expense. The value of the services and benefits in cash is assessed on the basis of cost. Social benefits do not include the value of uniforms and work clothing issued to manual and non-manual workers, reimbursable expenses such as travel allowances, dues, costs of representation, etc. incurred by workers at the cost of the establishment, or medical examinations which workers are required to undergo at the employer's request.

Data are also collected separately on the total cost of the benefits allotted to manual and non-manual workers; they include those which have been distributed during the month, regardless of the fiscal year to which they correspond.

Hours of work

These refer to the total of hours worked by manual and non-manual workers (permanent and casual workers) during the month. They include normal hours of working and overtime actually worked by all manual and non-manual workers, including time normally spent in preparation for work and time taken up on maintenance of machinery and cleaning of tools during the working day. They exclude time when work is suspended because of public holidays, strikes, labour disputes, technical stoppages, vacation, leave in the event of sickness or accident and maternity leave, all work stoppages caused by nature, and any other event which causes an unusual stoppage of work.

International recommendations

The concept of compensation of employees used in the survey meets the recommendations of the United Nations regarding industrial statistics and the System of National Accounts. It is also very close to the concept of labour cost. The definition of hours actually worked conforms to the corresponding international recommendations.

Classifications

Components of labour cost / compensation of employees

Data are classified by the three major components.

Industrial

The 1975 Catálogo Mexicano de Actividades Económicas is used. This is compatible with the International Standard Industrial Classification of all economic activities (ISIC), Rev. 2, 1968.

Occupational

Not relevant.

Others

The data are classified by category (manual or non-manual workers).

Sample size and design

Statistical unit

The sampling unit is the manufacturing establishment. An establishment is defined as any economic unit which, in a place defined by permanent buildings and installations, brings together resources under a single ownership or authority, in order to develop, for its own benefit or for a third party work of assembly, processing and transformation, total or partial, of raw materials, terminating in the production of related goods and services, which fall mainly under one single branch of economic activity.

Survey universe / sample frame

The frame is the list from the 1980 industrial census, lists from other industrial surveys and the special annual survey.

Sample design

The sample is purposive and has a high degree of representativity at the level of the class of activity. 3,218 major establishments according to the definition employed in the 1990 industrial census, i.e. establishments which employed six or more persons and had an income of at least 3,000 pesos, were selected. With regard to the number of establishments, the survey covers more than 20 per cent of all census units defined as major, and brings together over 70 per cent of the gross value of output in manufacturing in the industrial census.

Field work

Data collection

Information is obtained by deferred interview, i.e. enumerators from the regional offices visit the establishments each month, deliver the questionnaire and give advice on filling it in, explain difficult points and finally collect the completed questionnaire at an agreed time.

Survey questionnaire

The form contains four main sections, covering the following variables:

employees: monthly average by category,
wages, salaries, social benefits and taxes,
hours worked by manual workers and salaried employees, and
net sales and quantities produced by product.

Instructions regarding definitions, inclusions and exclusions form part of the questionnaire.

Substitution of sampling units

Not relevant.

Data processing and editing

A computerized system is used, containing a programme for entering data, an interactive programme for correction and a programme for the overall processing of information. Each of these has an integrated programme for detecting errors according to the phase of information processing.

Types of estimates

Total employment (by category), totals and averages of wages and salaries, hours of work and compensation of employees. Averages of wages and salaries, and averages of hours of work by category are obtained by dividing the total wages and salaries or hours during the month by the corresponding number of workers.

Construction of indices

Index numbers of paid employment and of hours actually worked are calculated, for all paid workers together and by category, by month and by group of classes of activity, with base 1980=100. Index numbers are also calculated for compensation of employees, by month and by chief components of compensation of employees, with base 1980=100.

Weighting of sample results

Not relevant. The data reflect the situation in the establishments selected.

Adjustments

Non-response

Not relevant.

Other bias

Not relevant.

Use of benchmark data

Not relevant.

Seasonal variations

Not available.

Indicators of reliability of the estimates

Coverage of the sampling frame

The 1980 Industrial Census provided the sampling frame. The survey is currently being updated on the basis of the directory of the 1994 industrial census.

Sampling error / sampling variance

Not calculated.

Non-response rate

Not calculated.

Non-sampling errors

Not available.

Conformity with other sources

Not relevant.

Estimates for non-survey years

Not relevant.

Available series

Since January 1987, detailed tables have been published on:

employees, manual and non-manual workers,
hours worked by manual and non-manual workers,
total compensation of employees, salaries, wages and social benefits,
total value of output,
total value of sales,
volume and value of output of the main products,

by class of activity.

History of the survey

The monthly industrial survey has been carried out since 1964. In 1987, improvements were introduced in the representativity and coverage of the survey. The classes of activity were increased from 57 to 129, the establishments surveyed were increased from 1,157 to 3,218 and the catalogue of products in stock was extended. A computerized system and methods of verification of data were designed and introduced, and manuals were compiled giving the criteria for collection. This survey is now in being updated on the basis of the 1994 industrial census directory. It is intended to extend the survey to 208 classes of activity and to more than 7,000 manufacturing establishments, and to employ the 1994 Clasificación Mexicana de Actividades y Productos (CMAP), which is compatible with the International Standard Industrial Classification of all economic activities (ISIC), Rev. 3, 1990.

Documentation

Instituto Nacional de Estadística, Geografía e Informatica: Encuesta Industrial Mensual (Mexico; monthly). idem: Avance de Información Económica - Indicadores del Sector Manufacturera (ibid.; monthly). idem: Mexican Bulletin of Statistical Information (ibid., quarterly). The results of the survey can also be supplied on diskette.

Confidentiality / Reliability criteria

The provisions of Article 7, para. 3 of the Federal statistics law at present in force lays down that data and information which private persons provide for statistical purposes are strictly confidential and may not be divulged in any circumstances under the name of the person; and that they are not used as evidence in court or out of court.

Other information

Data supplied to the ILO for publication

Data on the following are published in the Yearbook of Labour Statistics:

paid employment in manufacturing, in Tables 5A and 5B;
average hours actually worked and hourly and monthly earnings for manual workers in manufacturing, in Tables 12A, 12B, 17A and 17B;
average compensation of employees per hour in manufacturing, in Tables 22A and 22B.

Monthly series on paid employment (all employees) and average monthly earnings of manual workers in manufacturing are also published in Tables 3 and 8 of the Bulletin of Labour Statistics. Other surveys: An Encuesta Industrial Anual (Annual Industrial Survey) (EIA) is carried out with the same coverage and following the same concepts and definitions. The essential difference is that the EIA provides information for the structural analysis of industry as it covers topics such as electrical energy, stocks, fixed assets, amounts of raw materials consumed, etc. The results are not published. They can, however, be obtained from the INEGI on request. Estadística de la Industria Maquiladora de Exportación (Statistics of the export-processing industry) are also compiled monthly, covering nine Federal areas with export-processing enterprises. Data are collected on paid employment (manual workers and salaried employees), compensation of employees, (wages, salaries and social benefits) and hours actually worked, by category. The data are published monthly in the INEGI Boletín Mensual de la Estadística de la Industria Maquiladora de Exportación.