What city are we talking about? – KiwiBuild article misuses population statistics

This post first appeared on TraNZport and is republished with permission.

Yesterday there was an article in The Press about whether KiwiBuild should even be a thing in Christchurch. The gist of the piece is that property developers think the Christchurch property market, unlike Auckland and Wellington, is doing just fine, thank you very much, so let’s just leave it to the free market. Now, this is a transport blog, so I’m not going to get too much into the property side of things. However, what really bugged me about the article was the incorrect and misleading use of population statistics which essentially underpinned the entire argument of the article, which was well and truly on the side of the property developers who believed KiwiBuild isn’t necessary

How big is Christchurch, really?

In the article there is a section subtitled “How Fast is Christchurch’s Population Growing?“. It quotes Phil Twyford as saying that, despite Christchurch’s lower house prices, continued high population growth in Christchurch means that prices need to be kept within reach of first home buyers. Thus, keeping housing supply at a level that does this is essential to avoid a future “Auckland situation”. That’s a reasonably understandable point. The article then goes on to quote a KiwiBuild spokesperson as saying the following:

There is a need to increase the supply of affordable homes in Canterbury. Christchurch’s population grew by 7000 last year – the second largest population growth of any city in New Zealand, after Auckland.

“Population growth is projected to continue strongly with 150,000 more people over the next 30 years. That’s estimated to require 86,000 new houses.”

Okay, so that actually checks out. The Christchurch urban area did grow by 7000 people last year and the 150,000 extra people over 30 years estimate comes from a Greater Christchurch Partnership report, “Our Space 2018-2048”, the settlement pattern update using Census 2013 data as a foundation.  However, there is an inconsistency there that the journalist then goes on to build into their article that misrepresents the situation, and a few more things too that I will outline.

The article goes on to say that while Christchurch saw the second largest growth of any centre last year, it did so at a growth rate of 1.8 per cent, which is below the national average of 1.9 per cent, and only 37th in the country when it comes to percentage of growth. The article also appears to question the validity of these figures anyway because they are still using the 2013 Census as a basis.

The article uses the wrong population stats for the area it describes

The 7000 people Christchurch gained last year is within the urban area only, so that doesn’t include Rangiora, Rolleston, Woodend, Lincoln or West Melton etc. If we did include those centres, and the peri-urban areas around them, then Christchurch would be adding about 11-12,000 people per annum in an area with a population of a little under half a million, giving a growth rate of well over 2 per cent. Yet, the article specifically references a KiwiBuild project in Rangiora, and talks about “Christchurch” as being beyond the Statistics NZ defined urban area that the population stats are for (i.e. it talks about property developments in Rolleston, Lincoln etc). So, essentially, the population stats are being completely misused to present a particular argument.

There is, unfortunately, more to this. The Greater Christchurch Partnership report that is mentioned by the article is specifically in relation to the “greater Christchurch” as defined by the Greater Christchurch Partnership, i.e it is a wider area that includes Rangiora, Rolleston etc. So,the KiwiBuild spokesperson should not have used it directly in relation to last years growth of the urban area as they relate to two different measurement areas. However, if anything, the figure of 150,000 is quite conservative. If current rates of growth are maintained, then that figure could end up being more like 300,000. Even then, I wouldn’t be surprised for if it ended up being higher than that.

Finally, there is the implication that because these measurements are based on the 2013 Census data  as a foundation (because the 2018 Census figures are unavailable as of yet) then this questions the validity of population growth figures and therefore, somehow, this lends credibility to the claims that Christchurch doesn’t need KiwiBuild. This, of course, makes no sense, for the exact opposite could be said as well, and is probably just as likely to be true. That being that population growth stats are slightly under-presented.

So what does this have to do with transport?

Unfortunately it has everything to do with transport. If a lack of understanding due to ignorance is being used or manipulated to support policy directions, then that will permeate to other policy areas. Population statistics are essential for planning infrastructure, hence the attempt to make it look like Christchurch isn’t really growing that fast at all in order to say that KiwiBuild isn’t needed. Why would people do this? Ideology? Their bottom line? I don’t really know, for it isn’t the point of this blog post.

However, I do think it highlights that there is a real need to understand how our cities are truly shaped so that we can plan accordingly. This is vitally important in Christchurch’s case when it comes to improving transport an planning for things like rapid transit. Right now, the city’s population statistics are easily able to be manipulated by opponents of sustainable transport. Once these arguments are in the public domain, they are incredibly misleading if you don’t have the right knowledge and context.

I am currently working on a more in-depth piece about this very issue, with a particular focus on greater Christchurch as it provides the very best, and most complicated, example of this. However, this newspaper article really touched a nerve, so I decided to post this simplified version. I will, however, still publish that extended piece in the next week or two.

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