Sunday, September 7, 2014

How the NY subway tricks people out of their money using arithmetic

We’ve all been there. ... Yes, you need $2.50 to ride the subway, and you have $2.45 on your MetroCard. ...

It turns out the MTA has designed it that way. Imagine how many tourists come to NYC and leave with balances that never get used. Imagine how many people lose metro cards with those balances that never get used. And even if it gets used on a later refill, the MTA gets to collect the cash earlier this way! Win win for them, right?

But now, with some simple math, you can fight back!

First, let’s see how the MTA tricks you out of your money earlier than you might want to release it to them.

When you are buying a MetroCard, you can get a 5% bonus if your purchase is big enough. So you get the following screen early on in the purchase process:



If you click the button on the left, they just got you. Your card will have $9.45 on it, meaning you will get 3 rides and end up with $1.95. ...

Let’s say you don’t take the bait. You click MetroCard. Then you get this screen with three new short cuts:



... But wait a minute. One button leaves you with the same $9.45 card, and gives a remainder of $1.95 after just three uses. The next one is even more frustrating: you end up with a $19.95 card, leaving a remainder after 7 uses of $2.45! That’s right, the nickel we were talking about earlier. The last option does not leave you much better off. You’ll get a $40.95 card, which leads to $0.95 on your card after you use 16 rides. So all three buttons presented leave quite a bit of “insufficient fare” on the card.
So how do you fight back Well, click “Other Amounts” and type your own values:



and remember these three magic numbers: $9.55, $19.05 and $38.10. That’s right. Never use the short cuts. Just type in one of those numbers.

Once you do, you’ll see your excess balances nearly vanish once you apply the 5% bonuses. ...

So in closing, Math is useful. And luckily, you don’t have to be Einstein to outsmart the MTA.
--Ben Wellington, IQuantNY, on overcoming evil nudges