Mexico (2)
Title of the survey
Encuesta Nacional del Sector Formal de la Industria de la Construcción
(National Survey of Formal Sector Construction)
Organization responsible
Instituto Nacional de Estadística, Geografía e Informática (INEGI)
Periodicity of the survey
Quarterly.
Objectives of the survey
To obtain information on the economic performance of formal sector
construction.
Main labour topics covered by the survey
Employment and earnings; together with purchases and consumption of
building materials used by the enterprise and value of output generated
by the enterprise, by type of work, manner of execution, use and
geographical location.
Reference period
Each month of the quarter.
Coverage of the survey
Geographical
The whole country (the 32 Federal states).
Industrial
Construction.
Establishments
Only those belonging to the formal sector.
Persons
All employees (salaried employees and manual workers).
Persons who have given professional services to the establishment
exclusively for a fee, commissions, etc., but who do not form part of
the establishment, are excluded. Home workers and unpaid family workers
are also excluded.
Occupations
Information is not collected by occupation but by category of employee.
Concepts and definitions
Employment
Employed persons, i.e. employees comprise salaried employees
and manual workers (temporary or permanent) who worked in the enterprise
during the month of reference, under the control or management of the
enterprise, for a fixed or stated remuneration. Included are workers on
leave because of sickness or vacation, strike or temporary leave of
absence, paid or unpaid.
Persons on indefinite leave, in retirement or not paid are excluded,
together with workers subcontracted from other enterprises.
Employees are divided into:
- non-manual workers: workers with tasks of direction, management,
accountancy, sales, records, general or office work and persons
specializing in planning. Data are collected separately on:
- permanent employees: persons employed on contract for an unlimited
period,
- temporary employees: persons employed on contract for a limited
period or for a specific job;
- manual workers: workers directly engaged in the different stages
and processes of building, such as masonry, plastering, joinery,
electricity and painting; mechanics and drivers, etc. They include
cleaners, caretakers and storemen. Data are also collected separately
on:
- permanent workers: persons employed on contract for an unlimited
period,
- temporary workers and piece workers: persons employed on contract
for a specific job or specific work.
Earnings
These cover all payments made to paid workers during the reference
period, taking into account overtime, extra work, year-end bonuses,
premiums, incentive pay, payment for vacation and temporary leave of
absence, before deductions for tax, social security, trade-union dues
and the like.
Data are collected on the earnings for each of the categories and
sub-categories of employees.
Hours of work
Not relevant.
International recommendations
The concept of employed persons corresponds to that of employees.
The definition of earnings corresponds to the concept of earnings in
cash contained in the international recommendations. It includes both
regular and irregular payments. It excludes earnings in kind, however.
Classifications
Industrial
Not relevant. The survey covers construction only.
Occupational
Not relevant.
Others
Data are classified by category and sub-category of employee, the legal
status of the enterprises (individual/family or type of association) and
the sector (public or private).
Sample size and design
Statistical unit
The sampling unit is the construction enterprise, i.e. any
legal entity which, under a single proprietor or single management, and
physically situated in a permanent place (the domicile or head office of
the enterprise), is devoted chiefly to the performance of building work
on new constructions, demolition, improvements, repairs and major
maintenance of buildings already in existence. The enterprise can
consist of one or more units or establishments in various physical
locations, provided that they belong to the same company.
Survey universe / sample frame
The frame used is the list of enterprises registered with the national
chamber of the construction industry. Updating is carried out every
year during the first month of the year.
Sample design
The sample is probabilistic and refers to a selection of 3,300
enterprises.
Field work
Data collection
Data are collected by means of personal interviews carried out by
interviewers from the regional offices of INEGI.
Survey questionnaire
The form comprises four main sections, covering the following variables:
- Section 1: collects information on employment and earnings for each
month of the quarter and for each employee category and type of
contract,
- Section 2: covers purchases and consumption of construction
material by cash value per month,
- Section 3: covers the value of output by the type of construction,
the form of performance, the contracting sector and the geographical
location, per month.
Instructions regarding definitions, inclusions and exclusions form part
of the questionnaire.
Substitution of sampling units
The sample units are not replaced in the event of non-response.
Data processing and editing
This takes place in the following stages: when the information is
collected, it is assembled at the central offices, passing from there to
the phase of verification and coding, in which the consistency of each
questionnaire is studied. If there are inconsistencies, they are
discussed with the respondents over the telephone. When each
questionnaire has been checked, it is sent to the computer department,
where the information is entered and processed for the subsequent
systematic compilation of tables.
Types of estimates
Total of employed persons (by category) and earnings per person employed
(by category) in nominal and real terms.
Average earnings by category, obtained by dividing the total of monthly
earnings by the corresponding number of workers (manual and non-manual
workers).
Construction of indices
Not relevant.
Weighting of sample results
Weights are used according to the size of the enterprise. The
information presented thus matches the total coverage of the industry.
Adjustments
Non-response
The sample design takes into account the non-response rate, which
ensures that each collection of data counts as a representative sample
of the industry.
Other bias
Not relevant.
Use of benchmark data
Not relevant.
Seasonal variations
Not relevant.
Indicators of reliability of the estimates
Coverage of the sampling frame
100 per cent of formal sector construction.
Sampling error / sampling variance
The sampling error (5-10) is taken into consideration in calculating the
sample size.
Non-response rate
This is worked out on the basis of the collections of data and is taken
into account for the production of new sample designs.
Non-sampling errors
Not relevant.
Conformity with other sources
Not relevant.
Available series
Employed persons, by category; average earnings, by category; value of
purchases and consumption of construction, by the enterprises; and
other industrial statistics. All variables are given per month in
current, and constant values.
History of the survey
The national survey of formal sector construction began in July 1983,
and in course of time has undergone a number of alterations to its
variables, up to the present, when information is produced by stratum
for each of the 32 Federal states.
Documentation
Instituto Nacional de Estadística, Geografía e Informática:
Avance de Información Económica - Industria de la Construcción
(Mexico City, monthly).
More detailed results on earnings by sub-category, which do not appear
in the regular publications, can also be obtained on request.
Confidentiality / Reliability criteria
Article 38 of the Law on statistical and geographical information states
that information may not be supplied to any person as individual data or
by name, nor may it be used as evidence before administrative or fiscal
authorities, not in court or out of court.
Other information
Data supplied to the ILO for publication
Data on the number of paid workers in construction are published in the
Yearbook of Labour Statistics, in Table 7.