For those involved in labour market analysis and planning, it is useful to be able to use data for labour market areas.
To meet this need, labour market areas are defined to reflect areas where the bulk of the resident population also work within the same area.
Defining labour market areas requires the analysis of commuting patterns, and the Office for National Statistics (ONS) has worked with Newcastle University to apply a complex allocation process to define a set of Travel to Work Areas (TTWAs) for the whole of the UK.
The current criteria for defining TTWAs is that generally at least 75% of an area's resident workforce work in the area and at least 75% of the people who work in the area also live in the area. The area must also have a working population of at least 3,500. However, for areas with a working population in excess of 25,000, self-containment rates as low as 66.7% are accepted. TTWA boundaries are non-overlapping and contiguous, and cover the whole of the UK. TTWAs do cross national boundaries, although no account is taken of commuting between Northern Ireland and the Republic of Ireland.
The resulting pattern is that, although the definitive minimum working population in a TTWA is 3,500, many are much larger - indeed, the whole of London and surrounding area forms one TTWA.
The 243 current TTWAs were defined in 2007 using 2001 Census information on home and work addresses, and are based on Lower Layer Super Output areas in England and Wales, data zones in Scotland, and Super Output Areas in Northern Ireland.
We see once again a reduction in the number of TTWAs as the trend in more and longer distance commuting increases: in 1991 there were 314 TTWAs and in 1981 there were 334.
ONS is drawing up plans to create updated UK TTWAs using commuting flow data from the 2011 Census. It is intended that the updated TTWAs will be published in 2015.
If you have any questions on TTWAs please email firstname.lastname@example.org.