MKA Criticisms of Tesco Household Survey/Market Share RIA Approach.

• 4th December 2013
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• mkaplanning

We presented a number of objections to the Planning Appeals Commission for the proposed two Tesco superstores at Buncrana Road on behalf of our Clients – Northside Shopping Centre.  A key focus of our objections was the Retail Impact Assessments (RIA) for the proposed two Tesco foodstores at Buncrana Road, Derry and the household survey (HS) that underpinned it. Tesco’s Consultants adopted the market share approach to the RIA.  In this type of RIA the market share of the particular retail stores within the catchment were calculated based on the results of the HS.

 We had a number of fundamental objections to this approach.

 1.       The HS consisted of 600 surveys with the catchment area population of circa. 110,000 divided up into 12 zones and 50 surveys carried out in each zone.

  

Paragraph B33 of the Best Practice Guide on Retail Need, Impact and the Sequential Approach recommend a minimum of 100 completed questionnaires per zone.  The proposal only provides 50 per zone.   

Table MKA 1 – 2011 population within all 12 identified zones  

Zones	2011 population
C1	20374
W1	7922
W2	10625
W3	8313
C2	1644
C3	30212
C4	8322
W4	8947
W5	3941
C5	2669
C6	3555
C7	2723
TOTAL	109247

The survey size is therefore inadequate from the outset.   

 2.       Over 50,000 people on the Cityside are within Zones C1 and C3 represented by just 100 surveys (16.6%). The other 60,000 population who live within the catchment (53.6%) are represented by 500 of the 600 surveys (83.3%).     Zones C1 and C3 are 46% of the entire catchment population and 73% of the Cityside population of 69,499.  C1 and C3 are the key areas of the Cityside that contain the vast majority of the population and the major retail food stores.  Zones C1 and C3 have 73% of the Cityside population and are represented by just 100 of the 600 surveys (16.6%).  

Table MKA 2 – Population of Zones C1 and C3. 

Zone	Population
C3	30212
C1	20374
Total Population	50586

Any HS trying to identify shopping patterns and market shares of retail stores particularly on the Cityside (where the appeal site is located) should have concentrated their survey work on Zones C1 and C3 where the bulk of the population reside.  The Tesco’s HS does the exact opposite.  It focuses on the other Cityside zones where only a small proportion of the population reside.

 3.       The population of Zones C1 and C3 and their shopping patterns are clearly under represented in the HS.     The under representation of the shopping patterns of the population in C1 and C3 and the over representation of Zones C2/C5/C6 and C7 (primarily Donegal shoppers) with a total population of 10,591 less than 10% of the catchment can be clearly seen in Table MKA 3.

Table MKA 3 – Cityside Zones, Population and Representation Ratios.

Zone	Population	Survey per Population
C1	30212	1 survey result for every 604 people
C3	20374	1 survey result for every 407 people
C5	2669	1 survey result for every 53 people
C7	2753	1 survey result for every 54 people

 4.        Zones C2/C5/C6 and C7 have been given 200 surveys in the HS (33%) – 1/3 of the entire survey despite the fact that their population equates to less than 10% and they are outside the primacy catchment.  Their surveys have also been carried out face to face rather than by telephone.   The shopping patterns and market share of this 10,591 people are given significantly greater weight within the HS than the C1/C3 population of 50,586 with only 100 surveys. 

C1 and C3 shopping patterns are clearly under represented and the shopping patterns of C2/C5/C6 and C7 are clearly over represented. 

 5.       This under representation is further emphasised by the fact that Zone C3 is the primary catchment area where Best Practice recommends that further in-depth sampling is carried out in these zones.  If one compares Zones C2/C5/C6 and C7 with Zone C3 in terms of population C3 with 30,212 i.e.  27% of the population catchment is only represented by 50 surveys while 10,591 people are represented by 200 surveys. 

The key issue in this HS is that shoppers in C3 are the ones most likely to shop in either Northside or Springtown District Centres.  The shopping patterns and market share of the population and these Centres with Zone C3 is under represented in this HS.

 6.       This unrepresentative approach to the HS skews the figures, it gives a greater weighting to the survey findings in the Donegal and Waterside zones and a lower weighting to the findings in Cityside Zones C1 and C3.  The HS overstates the most popular answers; it understates the least popular answers. The HS asks simple questions about where people shop and provides answers that relate to trips and not spending flows. 

These questions overstate the importance of the larger centres and stores, and can understate the smaller and less frequently visited stores.  The Best Practice guidelines point this out at Para. B.34 and the HS is in breach of this advice.

 7.       As the HS is flawed and unrepresentative of the shopping patterns within the particular zones the market shares of the retail stores are also flawed and unrepresentative.  This skewed approach ensures that both Northside and Springtown Shopping Centres score very badly in terms of market share.

 8.       Telephone surveys are also biased against the population of C1 and C3 in that it is a telephone survey and many disadvantaged households in this area (one of the most deprived areas in NI) do not have landline telephones and some deprived residents who have landlines lack confidence are reluctant to get involved in surveys.