Nigeria

1.Title of the survey:

The Labour Force Sample Survey, which is part of the National Integrated Survey of Households (NISH).

2.Organization responsible for the survey:

Federal Office of Statistics.

3.Coverage of the survey:

(a) Geographical:

The whole country.

(b) Persons covered:

All persons living in private households and residing in the country. Members of the households who are temporarily absent but are expected to return (e.g. members travelling, members in hospital due to illness, children staying in a boarding school, etc.) are included in the household; temporary guests and visitors are excluded. Thus each person is given an even chance of inclusion in his/her own household.

Excluded are members of the armed forces and persons living in institutions like prisons and mental asylums.

The economically active population comprises persons aged 15 through 59 years.

4.Periodicity of the survey:

Quarterly, in March, June, September and December of each year.

5.Reference period:

The week (from Monday to last Sunday) prior to the interview.

6.Topics covered:

The survey provides information on employment, unemployment, underemployment, hours of work, income per week, duration of employment and unemployment, industry, occupation, status in employment, level of education and usual activity.

7.Concepts and definitions:

(a) Employment:

The employed are "all persons within the specified age limits who performed some work for pay, profit or family gain during the reference period. Also included are those persons with work attachments who are temporarily away from work during the reference period under consideration, on account of illness, injury, bad weather, vacation, etc. Employers, own-account workers, unpaid family workers and members of producers' cooperatives fall under this category and are distinguished as 'at work' or 'not at work' according to their state of activities in the reference week. The notion of 'some work' is interpreted as work for at least one hour."

Also included are:

  1. full- and part-time workers seeking other work during the reference week;
  2. full- and part-time students working full- or part-time;
  3. persons who performed some work for pay or profit during the reference week while being subject to compulsory schooling;
  4. paid and unpaid apprentices and trainees;
  5. participants in employment promotion schemes;
  6. paid and unpaid family workers;
  7. private domestic servants;
  8. members of producers' co-operatives;
  9. persons with a job but temporarily absent due to labour-management dispute, mechanical breakdown or other reduction in economic activity (including persons laid off for up to 30 days), i.e. persons who have a strong link with their employer.

Excluded from the employed and considered as inactive are persons engaged in own housework and persons doing unpaid community or social work. Members of the armed forces are not covered by the survey.

(b) Underemployment:

Underemployed persons are classified according to three criteria:
  1. underemployment by volume of work or time
  2. underemployment by income
  3. underemployment by mismatch of income and qualification/experience.

Underemployment by volume of work is derived from the replies given by the employed persons on their hours of work and involuntary reasons for working less than the normal duration of work. The involuntary reasons may be: slack work or slack season, material shortages, repairs to plant or equipment, failure to obtain full-time job, etc. The concept of underemployment for not paid labour force is also judged by identifying those persons who would accept additional work or want to change job, regardless of the number of hours worked.

Income and mismatch characteristics are derived from some of the replies to the national questionnaire, but elaborate studies have been deferred.

(c) Unemployment:

The unemployed comprise all persons who, during the reference period,
  1. were looking for work,
  2. wanted to work but did not look for work because of illness, bad weather, etc.,
  3. did not look for work because they thought that no job was available,
  4. have a weak link with their employer (i.e. laid-off workers who are seeking work and are currently available for work).

Also included are persons without a job and currently available for work who have made arrangements to start a new job on a date subsequent to the reference period; full- and part-time students seeking full- or part-time work; and seasonal workers awaiting agricultural or other seasonal work.

The notion of "registered unemployed" is not applicable in Nigeria. Job search is assessed on the basis of the respondent's declaration that he/she wants a job and looked for work; no methods of job search are specified.

(d) Hours of work:

They refer to hours worked during the reference week, in main and secondary jobs separately, excluding lunch and recreation time.

(e) Informal sector:

This topic is not covered by the survey.

Information is collected on the "normal

(f) Usual activity:

activity" of each person, if it is different from the work done during the reference week. Normal activity is defined as the work done most of the last one year and is reported in terms of normal occupation or usual status like student, housewife, etc.

8.Classifications used:

Employed persons and unemployed persons with previous work experience are classified by industry, occupation, and status in employment. All household members are classified by level of education.

(a) Industry:

The industrial classification is a combination of 2-digit and 3-digit levels of the International Standard Industrial Classification of all Economic Activities (ISIC-1968). Data are published under 10 groups.

(b) Occupation:

The occupational classification is based on a combination of 3-digit and 5-digit levels of the International Standard Classification of Occupations (ISCO-1968). Data are published under 10 groups.

Both industrial and occupational classifications take into account specific industries and occupations which are of importance or interest in the national context.

(c) Status in employment:

Data on main and secondary jobs separately are collected according to the following status categories:
  1. Employee
  2. Employer
  3. Company Director
  4. Self-employed with employee(s)
  5. Self-employed without employees
  6. Family Assistant
  7. Member of Cooperative

In addition, the following status groups are distinguished in agriculture: (i) Independent Farmer, (ii) Tenant Farmer, (iii) Share Cropper, (iv) Mixed Farmer, (v) Daily Farm Labourer, (vi) Others.

For publication purposes, data are classified under the following groups which are linked to the International Classification of Status in Employment (ICSE):

  1. Employer,
  2. Employee,
  3. Own-account worker,
  4. Unpaid family worker,
  5. Other.

(d) Level of education/qualifications:

Every member of the sampled households, including those who are outside the labour force, is classified according to his/her level of education and training. This classification is linked to the International Standard Classification of Education (ISCED-1976) and distinguishes the following levels:
  1. No schooling
  2. Primary education (completed or not completed)
  3. Secondary education (completed or not completed)
  4. College of education
  5. Polytechnic
  6. University

9.Sample size and design:

(a) The sample frame:

The sample frame for the current survey programme of NISH is a master sample of enumeration areas (EAs) selected by double sampling from an area frame constructed for the 1973 Population Census. The EAs are classified as urban and rural, the former comprising localities with a population of 20,000 or more. The average population is about 600 persons in urban EAs and 450 in rural EAs.

The frame is updated by re-demarcation of EAs and new listings of households.

(b) The sample:

In the first phase of the sampling procedure, each of the 19 States was treated as a separate stratum and a sample of 200 EAs was selected for each State. The EAs were sub-stratified as (a) State Capital, (b) other towns, and (c) rural areas, and the sample was allocated to the sub-strata as follows: State capital, 46 EAs; other towns, 69; rural areas, 86.

For the State Capital and rural areas, the first phase selection was done in a single operation, and the EAs were selected systematically with equal probability. In the other urban stratum, the sample was selected in two stages, using towns as first stage units and EAs within selected towns as second stage units (except in States with less than four towns in which case the EAs were selected in a single operation). In each State a sample of three towns was selected with probability proportionate to the number of EAs in each town, and from each selected town, a sample of 23 EAs was selected systematically with equal probability.

For the second phase, in each of the selected EAs all the households were listed with their basic characteristics, including the information needed for the identification of agricultural households. From the first phase sample of 200 EAs nine sub-samples, each consisting of eight urban and six rural EAs were selected with probability proportionate to the number of households in the urban sector, and to the number of agricultural households in the rural sector. These nine sub-samples have been used as the master sample for the integrated household survey programme since 1981/82. The master sample thus includes 72 urban EAs and 54 rural EAs per State, i.e. 1, 368 urban EAs and 1,026 rural EAs for the whole country, making a total of 2,394.

For the survey programme each year, five of the nine sub-samples selected at random are used, replacing one of the five by another each year. Thus, the effective primary sample for each survey round consists of 40 urban and 30 rural EAs per State, or 760 urban and 570 rural EAs for the country as a whole, making a total of 1,330.

The ultimate sample size varies from survey to survey within the NISH context. The Labour Force Survey conducted in December 1983 on a pilot basis covered 60 urban and 46 rural EAs and surveyed 20 households per EA. A larger survey based on 180 urban and 140 rural EAs was conducted in December 1984 with 20 households per EA and was repeated at half-year intervals in 1985. It was followed by a quarterly survey initiated in 1986 more or less with the same sample size, but with a 50 per cent overlap from quarter to quarter. The effective sample size is about 4,500 households per quarter.

(c) Rotation:

A rotation system has been adopted to ensure a 50 per cent overlap from quarter to quarter.

10.Field work:

(a) Data collection:

Data are collected quarterly, in one month of the quarter (March, June, September and December). Personal interviews are carried out by a permanent survey team of the Federal Office of Statistics.

(b) Substitution of ultimate sampling units:

Not applicable.

11.Quality controls:

Field enumerators' work is supervised by headquarters staff members. During the processing stage, controls are made using special forms.

12.Weighting the sample:

Not available.

13.Sampling errors:

Not available.

14.Adjustments:

(a) Population not covered:

No adjustments are made for the excluded population groups (see under Coverage of the survey).

(b) Under/overcoverage:

Not available.

(c) Non-response:

Not available.

15.Seasonal adjustment:

No adjustment is made for seasonal variations.

16.Non-sampling errors:

Not available.

17.History of the survey:

The Labour Force Survey is part of the National Integrated Survey of Households (NISH) which comprises a General Household Survey (annual), a National Consumer Survey (annual), a Rural Agricultural Sample Survey (annual), a Health and Nutrition Status Survey (1983/84), a periodic Labour Force Survey (initiated in 1983) and an Agricultural Sample Census (1984/85).

A pilot Labour Force Survey was conducted in December 1983 and was followed by a larger survey in December 1984. In 1985, the survey was conducted in two rounds (in June and December) and in 1986 it became quarterly.

18.Documentation:

For latest results of the survey, see:

Federal Office of Statistics: "Labour Force Survey" (quarterly) (Lagos); published about six months after each quarter.

The results are also available on magnetic tape, and non-published results can be made available upon request.