From Roland McKinney
Although Graham Moore illustrates some of the flaws in the Draft Local Plan, the picture is actually much worse than he describes. This is because the projections made by the Office of National Statistics (ONS) that were used by all the consultants who produced the reports in the so called “evidence base” were flawed; they were based on a dataset derived from the 2001 census.
The result of the 2011 census showed that the ONS were overestimating the growth in Guildford’s population, so they revised their dataset, and their projections. New versions were published in May 2014. This means that any [previous] ONS projection used in the production of the evidence base is flawed.
Guildford Borough Council (GBC) were aware of these flaws, they were pointed out to them by the Guildford Society through their work on student numbers, and in subsequent communications with the ONS. Yet no effort was made before the release of the Draft Local Plan to correct these known errors. How can members of the public properly assess the evidence base, when it contains statistics known to be inaccurate?
Graham Moore was absolutely correct in saying that GBC merely cranked a handle and extrapolated ONS projections. The ONS is very clear that this should not happen, that their numbers do not contain any trend analysis, absolutely essential when developing forecasts.
This is not good enough. GBC and its consultants should have started with an examination of the base ONS statistics and where there were anomalies, these should have been explained by examining underlying trends.
By way of examples of anomalies, the ONS use five-year moving averages in their population projections, but measures such as birth rates and net migration vary considerably with time, so the five-year moving average may not provide a good guide to the future.
Another classic example is the net migration rate. This varies considerably over time, so using a five-year average is very likely to overstate the net migration rate in some local authorities – and does so for GBC. Yet there was no examination of these statistics, no attempt to identify trends, nor was there any attempt to understand the driving forces behind trends.
Without this analysis, mechanical projections are next to useless, and when taken with the inclusion of projections based on statistics known to be incorrect, render the whole of the draft Local Plan unfit for purpose.
But as Susan Parker [Guildford Greenbelt Group] has said, it is essential to comment. We should all let GBC know what we think of their contempt for the consultation process.
Guildford Borough Council were asked to respond to this letter. No response has been received.