[18-03-2009] Sample Coverage and Definitions
The sample of addresses for the LFS is obtained from the Valuation & Lands Agency list of domestic properties in Northern Ireland and the quarterly survey has been designed to give reliable estimates of level for each quarter, as well as change over consecutive quarters.
These aims have been achieved by using an unclustered sample with a large element of overlap between quarters. The theoretical sample for each quarter consists of around 3,250 addresses, made up of five 'waves', each containing approximately 650 private households. Every sampled address is interviewed in five successive quarters, such that in any one quarter one wave will be receiving their first interview, one wave their second and so on, with one wave receiving their fifth and final interview. This results in an 80% sample overlap between quarters.
As mentioned, the theoretical sample for the NIQLFS comprises 3,250 addresses. However, due to the cumulative effect of refusals and ineligible addresses, the number of 'active' addresses is approximately 2,700 each quarter.
At each address, information is collected on the economic status and activity of all residents aged 16 and over during a specified week in the quarter (termed the reference week). Household size and composition was also recorded for each address.
LFS respondents aged 16 and over are classified into two main categories:
persons who were economically active or,
persons who were economically inactive in the reference week of the survey.
The economically active comprise:
(a) People in Employment, AND
(b) Unemployed Persons
All other persons (not included in (a) or (b) above) are defined as economically inactive. This includes all those aged under 16 and students who were looking for work but said that they were not available to start work within two weeks because they had to complete full-time education.
IN EMPLOYMENT
· Those aged 16 and over who did some paid work in the reference week (either as an employee or self-employed); those who had a job which they were temporarily away from (on holiday for example); those participating in government training and employment programmes; and those doing unpaid family work.
EMPLOYEES
· The division between employees and self-employed is based on survey respondents' own assessment of their employment status.
UNPAID FAMILY WORKERS
· Persons doing unpaid work for a business they own or a business that a relative owns
UNEMPLOYMENT
· The International Labour Office (ILO) measure of unemployment used throughout this statistics notice refers to people without a job who were available to start work in the two weeks following their LFS interview and had either looked for work in the four weeks prior to interview or were waiting to start a job they had already obtained. This definition of unemployment is in accordance with that adopted by the 14th International Conference of Labour Statisticians and promulgated by the ILO in 1987.
· The unemployment rate is the percentage of economically active people who are unemployed on the ILO measure.
DURATION OF UNEMPLOYMENT
· Duration of unemployment is defined as the shorter of the following two periods:
(a) duration of active search for work; and
(b) length of time since employment.
· The short-term unemployed are those people who have been unemployed for under 1 year while the long-term unemployed are defined as those who have been unemployed for 1 year or more.
