The area cost adjustment for the schools block of the dedicated schools grant for 2015-16 is based on a combination of a teacher cost adjustment and a general labour market specific cost adjustment for non-teaching staff pay.
Teacher cost adjustments for the four regional pay bands (and the area cost adjustment itself) was published in the technical note to “Fairer schools funding: arrangements for 2015 to 2016”: https://www.gov.uk/government/publications/fairer-schools-funding-arrangements-for-2015-to-2016
The general labour market specific cost adjustment was calculated and published by the Department for Communities and Local Government in “Methodology Guide for the Area Cost Adjustment 2013/14”: http://webarchive.nationalarchives.gov.uk/20140505104649/http://www.local.communities.gov.uk/finance/1314/methacas.pdf
The methodology for combining the teacher and general labour market elements into the area cost adjustment is described in Annex C of “Fairer schools funding 2015 to 2016”: https://www.gov.uk/government/consultations/fairer-schools-funding-2015-to-2016
A map showing the area covered by the Department’s definition of a) the West Sussex Fringe and b) the West Sussex Non-Fringe is attached.