Exactly how many ways are there to get an autism diagnosis?

Anyway, today I was busily trying to write a paper related to these issues and I got to wondering, just how many different ways are there to get an autism diagnosis?

So this is what I did. I made a spreadsheet in Excel which had 12 columns, corresponding to the 12 different boxes that can be ticked. I then filled each of the rows below with a different combination of ticks and crosses (actually 1s and 0s).

Altogether there were 4096 possible combinations of ticks and crosses, going from all crosses to all ticks with everything in between (mathematically inclined readers will spot that 4096 is 2 to the power 12).

Then I added a 13th column that showed for each row whether the particular combination of ticks and crosses would get you a DSM IV diagnosis of autistic disorder. Finally I added up the number of rows with a positive diagnosis.

The answer… drum roll… is (click here to read more.)