"Afford" is a four-letter word. You can break it into:

1) I have the cash ready to spend right now or in liquid assets.

2) I can get the cash, but from an account/asset I'd rather not withdraw from (IRA, jewelry).

3) I can go into debt to pay it, and it wouldn't make a big difference over the next year.

4) I can go into debt to pay it, but my financial situation would be close to bankruptcy over the next year.

5) I can't access that kind of money by any means.

A good survey should iron out this spectrum of "affording" the expense to make the result robust and easy to interpret.