Flow Data Information System

2001 Commissioned Table: C0310 Commuting - London detail

This table was originally created as a custom tabulation for the Greater London Authority.

Contains journey-to-work flows from wards in Greater London to Output Areas in Greater London. Note: this table uses Standard Table wards, a set of wards in which a small number of wards with low population counts were merged with neighbouring wards in order to create output. There are 5 such cases for wards in Greater London, all in the City of London.

Users can choose from 12 counts in 1 table, comprising 11 possible methods of transport, plus an all-persons total.

For flows within London to distinct OAs (or sub-ward aggregates), these data are thought to be more reliable that the standard 2001 SWS Level 3 data, as they are less strongly affected by disclosure control (see below).

All the 2001 SWS data have been derived from the 100% sample and include imputed households. Where workplace locations were unknown, these were also imputed.

Disclosure control

Data associated with residences in England and Wales (i.e. all of this dataset) have been modifed via a process known as Small Cell Adjustment Methodology (SCAM). The SCAM process is a disclosure control mechanism. For all tables process using SCAM, interior cells with a 'small' value have been adjusted. 'Small' values are understood to be in the range 0-3. Cells with an initial value of 1 have been rounded to either 0 or 3, with 0 being the more likely result. Cells with an initial value of 3 have also been rounded to either 0 or 3, but with 3 being the more likely result. Cells with initial values of either 0 or 3 have retained these values although in each case it is impossible to distinguish between rounded values and 'genuine' 0s or 3s. All sub-totals and totals have been re-calculated from the rounded cells.

There are three noticeable effects of SCAM

  1. Within-table modification. For the majority of outputs, it will be apparent that a large proportion of cells within any table are either 0 or 3, and that sub-totals and totals within the table are multiples of 3.
  2. Between-table variation. SWS Levels 1 and 2 contain several output tables, with the result that a number of values (e.g. 'total migrants') can be found in more than one table. Due to SCAM, these values may not be consistent between tables.
  3. Between-level variation. The three spatial levels for which the SWS are available were independently subject to SCAM. Thus, if a particular value (e.g. 'total persons') is calculated by aggregating from one spatial level to a higher one, and compared to the value found in the SWS data set for that higher level, those values are unlikely to be consistent.

Users are advised to ensure that data they use has been calculated by summing the minimum number of base values.

Citation information

The following statements should be attached to all output produced using this data set

Data from this set should be cited in a bibliography as:

Office for National Statistics, 2001 Commissioned Table: C0310 Commuting - London detail [computer file], UK Data Service

Further information

There are 1 tables defined for this data set:

The data are available for the following geographies:

Geographies of origin areasGeographies of destination areas
Supported directly
[i]UK Standard Table Wards 2001[i]UK Output Areas 2001
Supported via aggregation
[i]UK interaction data districts 2001
[i]UK Government Office Regions (1999-)
[i]CIDS 1991/2001 common geography - 'districts'
[i]2001 ONS ST Ward Classification Supergroup
[i]2001 ONS ST Ward Classification Group
[i]2001 ONS ST Ward Classification Subgroup
[i]2001 ONS ST Ward Demographic Indicator Deciles
[i]UK interaction data wards 2001
[i]UK interaction data districts 2001
[i]UK Government Office Regions (1999-)
[i]UK Standard Table Wards 2001
[i]CIDS 1991/2001 common geography - 'districts'
[i]CIDS 1991/2001 common geography - 'intermediate'
[i]CIDS 1991/2001 common geography - '100 zones'
[i]CIDS 1991/2001 common geography - 'city regions'
[i]UK Lower Layer Super Output Areas (LSOA) 2001
[i]UK Middle Layer Super Output Areas (MSOA) 2001
[i]2001OA Classification - Supergroup
[i]2001OA Classification - Group
[i]2001OA Classification - Subgroup

Output for geographies that are only supported via aggregation will take longer than for those supported directly

Table frameworks

Table 1: Mode of transport
Aged 16-74 in employment
Total 1
Works or studies mainly at or from home 2
Underground etc. 3
Train 4
Bus etc. 5
Taxi 6
Car - driver 7
Car - passenger 8
Motorcycle etc. 9
Bicycle 10
On foot 11
Other 12