Models in Public Sector Planning

Question 1

Why are SIMs not used in the public sector?

Answer 1

Aberdeenshire LA in 2004 said gravity models had too many flaws in their methods, data, forecasts and assumptions to be successful

Question 2

What did the public sector replace gravity models with?

Answer 2

Retail Impact Assessment (RIA)

Question 3

Case study: Bluewater, Kent

Answer 3

Largest retail park in Europe

Planners said there would only be impact on London and Croydon - NOT TRUE

Question 4

What was the outcome of the SIM used for Bluewater?

Answer 4

GMAP built a SIM to assess the impact
Found no -ve impact on London or Croydon
-Ve impact on small local areas e.g. Gravesend
Impact on vacancy rates e.g. 26% in Dartford

Question 5

What are the 5 steps in the RIA?

Answer 5

Step 1: consumer survey on current shopping locations - but issue as most would say ‘Leeds City Centre’ without specificity

Step 2: estimate expenditure rates

Step 3: Future expenditure predictions

Step 4: estimate turnover of existing centres based on survey and expenditure estimates e.g. if 90% said city centre then 90% expenditure allocated here - but issue is that some will shop in Headingley, but not say this, therefore misallocation

Step 5: estimate turnover of new centre - based on turnover to floorspace ratios by company)

Question 6

What happened with the Donaldson’s Report in 2005?

Answer 6

Used inaccurate pop. forecasts in Step 3 and so said that population of Wolverhampton would double thus there would be no -ve impact

But this was wrong

Question 7

What happened with the ISG Developments Southern in 2008?

Answer 7

Centre development in Stowmarket
Issue with Step 5: they estimated that turnover for the centre was > total expenditure in local economy but built it anyway!

Question 8

What did Khawaldah et al. (2011, 2014) do to show that there is space for SIMs in the public sector?

Answer 8

Used SIM in Silverburn to compare with RIA
Much better outcome:
RIA predicted turnover = £175.2 mil.
SIM = £154.6 mil
RIA predicted no deflections.
SIM predicted deflections in 10 locations

Question 9

Why have SIMs not been included in GIS software?

Answer 9

BENOIT AND CLARKE, 1997

ArcGIS includes it but flawed as no calibration - beta remains at 2 regardless

Therefore, better to manually create and calibrate SIMs