In accordance with the policy thrust of the Federal Government of Nigeria on poverty alleviation, the National Bureau of Statistics (NBS) had, in the recent years, embarked on the assessment and monitoring of poverty levels through the conduct of Core Welfare Indicator Questionnaire (CWIQ) surveys. These surveys were part of the efforts of the Bureau in providing information for the management of the Nigerian economy and society. Prior to the current survey, NBS had conducted six rounds of CWIQ survey. These surveys spanned 13 States across the six geopolitical zones in Nigeria, from 1999 to 2004. The National CWIQ Survey 2006 was the latest and by far the biggest survey conducted to date in the history of the CWIQ.
Worldwide, the Core Welfare Indicator Questionnaire Survey (CWIQ) is designed to collect household data useful in quantitatively profiling the well-being of the population. The 2006 Nigerian CWIQ was a nationwide sample survey conducted to produce welfare indicators for the population at national and sub-national levels, particularly Zones, States and Senatorial Districts. The Survey compliments 2004 Nigerian Living Standards Survey (NLSS) by NBS which profiled poverty in the country.
Kind of Data
Sample survey data [ssd]
Unit of Analysis
Community, household, individual
v1.0 - This is the first version used to generate the first set of tables
v1.1 - Editied version
v1.2 - Use of the new template, review the topic of classifiction and the keywords
The CWIQ collected information at three levels. Some information were collected from individual members of the household about themselves as individuals and their household as a unit. Some questions were also asked on the needs of the community and the types of development that had taken place in the community in the past five years. Thus, the information solicited from household members included:
(i) At the individual household member level – Demography Education Health Employment Child Under 5 years Gender (Contribution to Household activities and welfare)
(ii) At the Household level – Household Assets Household Amenities
(iii) At Community level – Social Project Self-Assessed Poverty.
Households and usual residents from households in the nationally sampled area.
Producers and sponsors
National Bureau of Statistics
Federal Government of Nigeria
Federal Government of Nigeria
The National CWIQ Survey 2006 was designed with Local Government Area (LGA) serving as the reporting domain. Data were then aggregated to give estimates at Federal Constituency (FC), Senatorial, State, zonal (geo-political) and national levels. Basically, a 2-stage cluster sample design was adopted in each LGA. Enumeration Areas (EAs) formed the 1st stage or Primary Sampling Units (PSUs) while Housing Units (HUs) formed the 2nd stage or Ultimate Sampling Units (USUs). The EAs as demarcated by the National Population Commission (NPopC) for the 1991 Population Census served as the sampling frame for the selection of 1st stage sample units. In each LGA, a systematic selection of 10 EAs was made. Prior to the second stage selection, complete listing of Housing Units (and of Households within Housing Units) was carried out in each of the selected 1st stage units. These lists provided the frames for the second stage selection. Ten (10) HUs were then systematically selected per EA and all households in the selected HUs were interviewed.
Deviations from the Sample Design
However, only 75,929 households were completely enumerated and this gave a response rate of 98.5 per cent, the remaining 1.5 per cent were recorded cases of respondents not at home, refusals, household not located, moved away and others.
A total of 77,062 households were covered from a sample of 77,400 households giving the survey a coverage rate of 99.6 per cent. However, only 75,929 households were completely enumerated and this gave a response rate of 98.5 per cent, the remaining 1.5 per cent were recorded cases of respondents not at home, refusals, household not located, moved away and others. 59,567 households were covered in the rural areas with a response rate of 98.7 per cent while 17,495 households were covered in the urban areas with a response rate of 98.0 per cent. Out of all the six zones, it was only the South-east that has the least response rate of 97.4 per cent followed by South-south with 97.9 per cent. The highest response rate is from the North-east with 99.1 per cent, followed by North-west 99.0 per cent, South-west 98.8 per cent, and North Central 98.4 per cent. Out of all the States Imo State has the least response rate of 94.2 per cent with 2,690 households and Kogi State has the highest response rate of 100.0 per cent.
Dates of Data Collection
Data Collection Mode
The fieldwork was monitored at several levels. At the outset of fieldwork, some of the NBS headquarters staff who conducted training at the 2nd level stayed on and monitored data quality during the first week of the fieldwork i.e. the week immediately after the training. Thereafter, the state officers assumed full responsibility for the quality of fieldwork in their respective states. Within each state, a monitoring team was constituted. The teams of supervisors and enumerators were shared between members of the monitoring team. Each monitoring officer was responsible for data quality in the assigned team(s). Amongst others, they made field visits to the team(s) to control data quality, received completed questionnaires and subjected them to further review before submitting satisfactorily completed questionnaires to the state coordinator.
The Zonal Controllers monitored the quality of fieldwork within their respective zones. They ensured that all the states within their zones were visited at least once before the end of the fieldwork.
A monitoring programme was packaged to serve as guidelines for all the three different layers of monitoring officers.
The Independent Monitors appointed by the WB also monitored the fieldwork throughout the states. Their comments and observations were directed towards the collection of good quality data.
Data Collection Notes
The training for fieldwork was conducted at two levels. At each level, the training covered survey design, roles of the field staff, classroom sessions on the questionnaire and manuals, mock interviews, role playing, questionnaire editing and field practice. Because of the newness of the scannable questionnaire, there were also practice exercises on hand printing and shading of bubbles. The results of the exercises were scanned and made available to each of the trainees for him/her to see his/her printing and shading errors. The exercises underscored the need for the printing and shading of responses to be as impeccable as possible.
The first level training served as the Training of Trainers (TOT) and was directed at the would-be trainers at the 2nd level. The training objectives at this level included familiarization with the survey instruments and preparation of the trainers for 2nd level training, session by session. The training lasted for 5 days. Senior staff from NBS Headquarters and the NBS Zonal Controllers formed the pool of the trainees at this level from which the trainers were selected. The final selection was on merit, based on the result of the test conducted at the end of the training.
The second level training was for the field staff which consisted of enumerators and supervisors recruited nation-wide, the NBS state officers and Directors of State Statistical Agencies with whom NBS had always collaborated in past surveys. Due to the large number of field staff, training at this level was decentralized. In all, there were 12 training venues spread over 6 training centres i.e. one at each Zonal Headquarters. The two training venues at a training centre were made to be as close as possible for effective coordination and monitoring of the training programme. The training was conducted simultaneously in all the 12 training venues and lasted for 10 days. Just as was the case at the first level, the final selection of the field staff was on merit, based on test conducted at the end of the training.
The Independent monitors appointed by the World Bank to monitor the implementation of the CWIQ Survey 2006 were also in attendance to attest to the quality of the training at the 1st level and 2nd levels of training.
National Bureau of Statistics
FSM and CSD
Three main instruments were designed for and used during the survey. They included the CWIQ questionnaire, the interviewer’s manual and the supervisor’s manual. The generic scannable CWIQ questionnaire was adapted to suit the country situation. Some modifications were however, made in the questionnaire after the survey in Benue. The modified questionnaire was then used for the CWIQ survey in Abia, Cross-River, Ekiti, Kebbi, Kogi, Yobe, Jigawa and Enugu in May to August 2002. The States covered in year 2003 were repeated for the year 2004. These include Abia, Cross-River, Gombe, Kebbi, Osun and Plateau States. Further modifications was done to the questionnaire in may 2005, there was total overhaul of some sections and the reference number was pre printed and at the same time reduced to 4 digit; while a new methodology which used hand printing recognition was adapted.
The questionnaire served as the main data collection instrument and captured the minimum information that allowed for identification of targets groups, provision of basic welfare indicators for measuring poverty and the capturing of information which measured access, utilization and satisfaction with services provided. The questionnaire did not cover measurement of indicators on child nutrition through anthropometric measurements. This was mainly due to inability to procure early enough, the necessary anthropometric equipment, namely, rollameter, microtoise and mother-and-child weighing scale.
During scanning, the scanner took an image of each page of the questionnaire through form processing software (Teleform), which subsequently evaluated the scanned images. Evaluated images that suggested possible errors in the questionnaire were verified and corrected by the data entry operator. Typical errors included unidentified pages that could not be evaluated; unrecognisable hand printed characters or bubbles, which were not completely shaded. The time required for image evaluation and subsequent verification depended on how well and legibly the questionnaire was filled in.
After all potential errors for an EA had been verified by the data entry operator; the data from the questionnaires was transferred to a shared folder in the desktop computer. The output of the scanner was then checked for consistency, omission, skips and other errors; the data was not transferred to the database until all such errors were corrected.
The data processing was organized to run concurrently with the fieldwork. That is, the programmers and their assistants participated in the training of the field staff and remained in the field for a number of days to further guide the enumerators on how to print the response and shade the bubbles according to the code of responses. Hence, the main data processing operation commenced two week after the commencement of the fieldwork. The CWIQ system consists of the following phase: Data entry, data validation and correction, and generation of survey results. Data entry consists of converting the information in the survey questions to a readable form for processing in the subsequent phases. This data processing system was adopted from the system developed by the World Bank in 1998 and 1999 and subsequently used for the pilot survey of Lagos State in July and August of 1999. Two processing centres were used and, the staff consisted of twelve (12) programmers and thirty four (34) computer assistants.
Twelve portable optical scanners each connected to a laptop computer were used for scanning the questionnaire on EA basis. The image evaluation and data verification were done simultaneously with the scanning of the questionnaire. Eight desktop computers were connected on a local area network (LAN) for error correction and data validation, and later converted to the database. Questionnaires coming from the field weekly by EA underwent identification and name confirmation at the processing centre using a master list of sample enumeration areas. The number of questionnaires and households for an EA were then counted to confirm that all the expected households in the enumeration area had been interviewed.
The confidentiality of the individual respondent is protected by law (Statistical Act 2007).
This is published in the Official Gazette of the Federal republic of Nigeria No. 60 vol. 94 of 11th June 2007. See section 26 para.2. Punitive measures for breeches of confidentiality are outlined in section 28 of the same Act.
A comprehensive data access policy is been developed by NBS, however section 27 of the Statistical Act 2007 outlines the data access obligation of data producers which includes the realease of properly anonymized micro data.
"National Bureau of Statistics, Core Welfare Indicators Questionnaire Survey 2006 (CWIQ 2006), v1.2, provided by the National Data Archive. http://www.nigerianstat.gov.ng/nada/index.php"
The user of the data acknowledges that the original collector of the data, the authorized distributor of the data, and the relevant funding agency bear no responsibility for use of the data or for interpretations or inferences based upon such uses.
DDI Document ID
National Bureau of Statistics
Federal Government of Nigeria
Major National Producer of Statistics
Accelerated Data Program
International Household Survey Network
Review of the metadata
Date of Metadata Production
DDI Document version
Version 02 (October 2013). Edited version based on Version 1.2 DDI (DDI_NGA_2006_CWIQ_v1.2_M) that was done by Nigeria National Bureau of Statistics and reviewed by Accelerated Data Program, International Household Survey Network.