It's how it's defined, so we've given a definition of STEM so that people can say, “Okay, I agree with that definition.” It's a variable that we've derived, so someone can say, “I derive it differently.” It is there, so I wouldn't want people to think that....
For instance, someone could say they want to use ages 25 to 28. That's a choice. Someone could say they would include physics teachers as part of STEM, and someone else would say they wouldn't. But we have physics teachers identified.