Question: Are there standardized methods for measuring capacities and specs?

Greetings all,

I've been looking at cars for the near future. I'm looking at econocars. I was really considering a Corolla, but I'm kinda drawn to the Scion xA at this point. (Yah yah yah, I know a lot of people don't like those. That's not my point).

My question is this: How in the heck is a Corolla rated at having 13.6 cubic feet of cargo room and a Scion xA at 12? That's only a 1.6 cu. ft. difference. I haven't gone to the dealerships and tried to compare this myself, but that just doesn't seem possible, from what I remember!

I've been scouring the 'net trying to find any sort info on how they take these measurements. (ie, For a hatchback, do they count the space all the way up to the ceiling? Do they include the space when you fold down the seats?) Passenger space in the xA seems to be very comparable to the Corolla, given the specs. I don't understand the cargo capacity though...

If anyone has info, I'd highly appreciate it.

Thanks,

Mike