Nigeria - Crime and Corruption Business Survey 2006, First round

In order to have a broad-based list of business and industrial establishments, three (3) sets of establishment frames were used. There are:
(i) Frame of Establishments from Economic Survey and Census Division of NBS.
(ii) Frame of Establishments from National Quick Employment Generation Survey (NQEGS) conducted by NBS in 2006.
(iii) Frame of Establishments from NBS/CBN/NCC collaborative Economic Survey conducted by NBS in 2006.

These frames were merged to give a single cleaned and validated frame.

The cleaning and validation of the frame involve the following;
(i) Elimination of duplications
(ii) Removing dead or moribund establishments from the frame
(iii) Filling in missing information where feasible.

This exercise was made possible through the combined efforts of the Economic Survey and Census Division, the National Accounts Division and the Methodology Division of NBS. Sample of 2,775 were selected from a frame of 15,556 which cut across 14 sectors of the economy namely:

(i) Agriculture (163)
(ii) Fishing (10)
(iii) Mining and Quarrying (75)
(iv) Manufacturing (474)
(v) Electricity, Gas and Water (66)
(vi) Building and Construction (137)
(vii) Wholesale and Retail Trade (450)
(viii) Hotels, Restaurants and Tourism (155)
(ix) Transport (200)
(x) Communication (92)
(xi) Financial Intermediation (233)
(xii) Real Estate, Renting and Business Activities (480)
(xiii) Public Administration (Government) (77)
(xiv) Education (163)

Selection Parameters:
In order to select the require number of establishments, some parameters were considered which include:
(i) Employment size, that is strata of 10 and above
(ii) Contribution of sector to GDP.
(iii) Purposive or prior knowledge of performance of sectors in the
economy.

Selection Procedure:
Basically, the sample design used for this survey was a two-level probability proportion to size (PPS) in which the contribution of each sector to the GDP formed the basis of allocation at the first level while the basis of allocation at the second level was number of establishments in each sector. A prior (purposive) allocation was also used to complement and boost the efficiency of the design.

Overall Sample Size:
The overall sample of establishments selected for this collaborative survey was 2,775. in choosing this sample size, many things were taken into consideration such as, limitation of resources, the need to ensure a manageable and controllable sample structure and the three important levels at which data are required for planning purposes, viz National zonal and state levels but basically, the estimates would be at national level.


The Sample Design can only be altered in case of political crises


A total of 2,775 establishments were selected nationwide and distributed among fifteen economic sectors in each state of the federation and federal capital territory (FCT) Abuja.

About eighty-one percent response rate was achieved nationwide. On the zonal level, south west zone achieved the highest response rate of 32.2percent in the country.


Sample weights were calculated for the data.

The weight for each sector will be equal to the reciprocal of the probabilities of sectors of the sample establishments in that sector multiplied by an adjustment/correction factor. These weights will be used to multiply sample values to obtain the population totals.