It is extraordinarily difficult to, yes. But then, people bank on using statistics to prove their point, and they tailor the way they present their evidence so it favors their stance.

Example: Only 1% of abortions in the U.S. over the last year were due to pregnancy by rape or incest, so it's not a viable argument to say that abortion should be legal to provide for those circumstance.

Sounds reasonable, I suppose, until you question 1% of how many over the last five years. If you're talking 1.5 million abortions, that's 15,000 women pregnant by rapists or family members...

Its not about the numbers shown, but the numbers not shown.