amastrosavvas / Commuting-Zones-Flows-EW

Harmonisation of local authority district (LAD) commuting matrices from the 1991, 2001, and 2011 UK Census and production of Tolbert-Sizer commuting zones. Coverage: England & Wales.

Commuting Zones of England and Wales

Output data

• ./output/lad20x_cz.csv contains a correspondence table matching harmonised local authority districts (LAD20X) covering the whole of England and Wales to Tolbert-Sizer commuting zones (CZ).

• ./output/commdat.RDS is a list containing the following data frames:

  • commdat[["dir annual by LAD"]] contains directed commuting flows by UK Census year (1991, 2001, 2011) and 2001 Interaction District pair (for 1991, 2001) or Census Merged LAD pair (for 2011).

  • commdat[["undir annual by LAD"]]contains gross commuting flows by UK Census year (1991, 2001, 2011) and 2001 Interaction District pair (for 1991, 2001) or Census Merged LAD pair (for 2011).

  • commdat[["dir annual by LAD20X"]] contains directed commuting flows by UK Census year (1991, 2001, 2011) and LAD20X pair.

  • commdat[["undir annual by LAD20X"]] contains gross commuting flows by UK Census year (1991, 2001, 2011) and LAD20X pair.

  • commdat[["resworkers annual by LAD20X"]] contains the resident workforce by UK Census year (1991, 2001, 2011) and LAD20X.

  • commdat[["minresworkers annual by LAD20X"]] contains the minimum resident workforce UK Census year (1991, 2001, 2011) and LAD20X pair.

  • commdat[["T-S annual by LAD20X"]] contains Tolbert-Sizer commuting dissimilarity measures by Census year (1991, 2001, 2011) and LAD20X pair.

  • commdat[["T-S average by LAD20X"]] contains average Tolbert-Sizer commuting dissimilarity across Census years (1991, 2001, 2011) by LAD20X pair.

• ./output/geometries/lad20x_cz.shp contains CZ boundary data.

• ./output/lad20x_CZ.png contains a map of LAD20X and CZ.

Method

• In harmonising commuting flows across Census years, the script prep_commdat.R converts the data to the harmonised local authority district classification (LAD20X) using the correspondence table ./rawdata/lad_lad20x.csv.

• Commuting zones are then derived by the script get_CZ.R in the following steps:

  1. For LAD20X pairs $rr'$ and Census years $t$, compute the Tolbert-Sizer commuting dissimilarity measure:

     $$D_{rr't}=\frac{Commuters_{rr't} + Commuters_{r'rt}}{min(ResidentWorkers_{rt},ResidentWorkers_{r't})}$$

  2. Compute the mean commuting dissimilarity across Census years $D_{rr'}$.

  3. Cluster the LAD20X using agglomerative hierarchical clustering with average linkage, based on $D_{rr'}$.

     Note: This approach is identical to that of Tolbert and Sizer (1996) with the exception that commuting dissimilarity is averaged across years instead of being taken for a single year.

Input data

• ./rawdata/lad_lad20x.csv is the correspondence table matching local authority district (LAD) codes that were live between 2001 and 2020 to a harmonised local authority district (LAD20X) equivalent or parent. The code and data used to produce this table are available in the Harmonised-Local-Authorities-EW repository.

• ./rawdata/geometries/lad20x.shp contains LAD20X boundary data.

• ./rawdata/commuting contains files downloaded from the the UK Data Service WICID database:

  • ./rawdata/commuting/UK DATA SERVICE - 1991 commuting flows by IDT01 (Set SWS C).csv holds the directed commuting flow matrix from the 1991 UK Census by 2001 Interaction Data District pair.

  • ./rawdata/commuting/UK DATA SERVICE - 2001 commuting flows by IDT01 (Set SWS 1).csv holds the directed commuting flow matrix from the 2001 UK Census by 2001 Interaction Data District pair.

  • ./rawdata/commuting/UK DATA SERVICE - 2011 commuting flows by CMLAD11 (Table WU02UK).csv holds the directed commuting flow matrix from the 2011 UK Census by Census Merged LAD pair.

References

• Tolbert, C.M. and Sizer, M., 1996. US commuting zones and labor market areas: A 1990 update (No. 1486-2018-6805). [link]

Attribution statements

• Contains public sector information licensed under the Open Government Licence v3.0.
• Contains Ordnance Survey (OS) data © Crown copyright and database right 2022.