How Cambridge Uses Cycling Statistics is Wrong
This morning, ONS published some more results from the Census, with the split between “ususal residents” and “term time residents” (ie excluding and including students).
“@ONS: Oxford & Cambridge populations drop by more than 10% out of term http://t.co/6UMclfFbjf” Crikey!
— The Dragon Fairy (@Puffles2010) September 24, 2014
That’s quite a lot even as a headline figure, but that 10% is when aggregated over the city: Cambridge students aren’t evenly distributed (yet).
Cambridge City Council publishes the figures it uses here, which has a huge spike for students, and which it uses for a range of things, such as travel planning, also using statistics from the census.
The press release announcing the travel to work analysis, published by ONS, highlights Cambridge cycling:
In Cambridge, 29% of working residents cycled to work, making it the local authority with highest rate of cycling to work.
Of course, census definitions of working residents do not include students, because students don’t work, they’re students. The form doesn’t ask students the question from which the cycling statistics are derived:
As a result, the models Cambridge City Council (and the county council) use, all dramatically undercount cycling in the city by at least 10% overall, and in the college-heavy wards of the city (ie, the city centre), by a dramatically higher amount. Of course, with undergraduates not being permitted cars in Cambridge, and postgrad use being heavily restricted, the car figures will be far more accurate. In short, none of the extra people in the huge spike in Phil’s population pyramid for Cambridge will drive, likely the majority will cycle.
Using other data sources, I wonder what it would look like if someone modelled impacts of the “normal practice” of college cycling…
I suspect it would lead to a dramatically different figures in some areas for cycling in Cambridge.
But would the County Council care?