Using data visualization to disinform

2 July, 2009 (12:10) | Uncategorized | By: jerome

Two weeks ago I have been at DD4D conference, conveniently located at my workplace. I will write some more on DD4D, meanwhile you can see this post on infosthetics by Petra and Marian. One of the things that struck me at DD4D was that several talks were about either data visualization for advocacy, or for education purposes. One speaker said that data visualization could be used to protect people against those who use numbers to mislead and disinform. Yesterday, I saw this typical example of such a manipulation, reminding of the famous Disraeli quote.

This is a poster for restaurants to display. Yesterday, VAT for restaurants in France was cut from 19.6% to 5.5%. This is the result over 10 years of lobbying. Initially, restaurants asked for a VAT drop and committed to cut their listed prices accordingly. That cut in price would have attracted more consumers, eventually generating more profit and possibly more tax money. That would have been a win-win-win situation for the restaurant industry, the consumer and the state.

But eventually, the changes that restaurants have agreed to their price structure are as follow. They would cut the listed price of up to 10 menu items by 11.8% to “reflect the tax drop”. In exchange, they are allowed to display this poster, on which the chart ominously promises a massive price drop.

In reality, 11.8% is not enough to offset the VAT drop.

That should have been approximately 13.4%  or 100*(1.196/1.055 – 1) . Fast-food chains only have to drop some of their prices by 5% to get the poster.

The poster claims: “a cut in VAT is a cut in prices!”. But what happens really? For most items, listed price (incl tax) is unchanged, which means their actual prices raise by 13.4%. And for the discounted items, the sales price excluding tax still raises by 1.4% (or 7.7% for fast-food chains).

Is this what was implied by the chart?

In the past two weeks, I have collected more examples of shameless lies backed by seemingly official numbers and charts, and will continue to collect them.

Write a comment