Reason I may yet write that stats/numbers book, #346

It’s just a little item in the April 2013 Fast Company, over in the bottom-left corner of a page, about the sales of steel wallets—mostly (I think) sold to people who are worried about RFID chips in their smart credit cards or passports being read.

Here’s a rough version of the graph that appeared with the piece:

When you see that, you’d tend to agree with the text of the article: “But apparently, the freak-out has already faded.”

But the graph is showing percentage increase in sales, year-over-year.

So, just for fun, let’s assume that 100,000 wallets were sold in 2006 (the actual number doesn’t matter) and draw a new graph using exactly the same data:


Now, does the assertion in the text seem quite as valid?

No? What? You say “Damn—those are pretty fast sales increases since 2009”? Well, you’re not Fast enough for FastCo.

Of course, there’s another aspect of this: We don’t know what the baseline for 2006 was–and percentages don’t mean much without a baseline. For all I know, maybe steel wallets were such a novelty item in 2006 that only 100 of them sold…which would make 2012 sales 1,905 and that Ginormous Jump from 2008 to 2009 an increase of…well, 675 wallets. Whoopdedo.


One Response to “Reason I may yet write that stats/numbers book, #346”

  1. Walt Crawford says:

    I should probably note that one of the common “X is Dead” techniques is to do a version of this–because rate of increase of sales has slowed down, even though sales are still growing, therefore the item being sold is dead, dead, dead.

    That’s how desktops and notebooks were variously declared dead a couple of years ago, for example.