I’m a bit of an Information Visualization junkie. I love good well presented data (I’m a fan of Tufte) and I dislike visualizations that are badly presented and/or misleading. I posted last week about various graphs showing relationships between urban density and transportation fuel consumption, some of which were hideous, some elegant, and some possibly misleading. I bemoaned the lack of access to the raw data, and a lively discussion followed about the believability of the relationship plotted on the graphs.
Yesterday I came across an interesting case, in the leaflet distributed to Torontonians from the city council, showing revenue and expenditure data. From a data visualization point of view, it looks like a series of poor choices were made, and I’m glad someone cared enough to point them out. But when you interpret these choices in the context of a right-wing Mayor who was elected on a tax-cutting, pro-car, anti-transit platform, it would appear these weren’t just mistakes – they were part of deliberate (if subtle) attempt to mislead:
- The leaflet shows a pie chart of revenue sources (in $billions) along side a pie chart of capital expenditure (in $millions), setting up a false impression that transit projects gobble up the majority of the city’s budget. The deception is enhanced by the fact that the largest segments in each pie are the same colour, and of a similar size. A quick glance therefore leaves the impression that nearly all our property taxes go to the Toronto Transit Commision.
- The leaflet fails to distinguish between gross and net expenditure. So a bar chart of budget items shows that the TTC (at $1.5 billion) is by far the most expensive item, followed by employment and social services. But the net cost of the TTC to the city is only about $0.5 billion, because most of its costs come from fares, while employment and social services are largely funded by the province. If you look at net costs (which is what most homeowners expect in answer to the question “how does the city spend our property taxes?”), the Police Service is by far the biggest item.
It’s the steady drip drip drip of this kind of misinformation that allows certain politicians to generate support for cutting budgets for transit and social services. Surely we should be investing in the kinds of community programs that reduce crime, so that we can trim that massive policing budget?
Here’s the chart on (gross) expenditures that they used:
and here’s the chart they should have used: