If you have a GuideStar account - the basic kind is free - or you consult the National Center for Charitable Statistics (h/t Mr. CKDH) or Drew's 990 database project comes to pass, you have access to reams of important information about the finances of the nonprofit of your choice.
The complexity of these forms varies enormously. I challenge you to understand the Metropolitan Museum of Art's 990, which includes information about attendance, assets (immense), income, donations, salaries, etc. The museum's assets include tens of thousands of art objects, valued at, I'm sure, billions of dollars, a huge and ever-expanding campus in NYC, etc., etc. It would take me a couple of days to fully comprehend the form.
But the 990 of a small nonprofit isn't that hard to deal with, and opera company 990s all have the same types of information.
For this reason, it's discouraging that I have now read, for the third time, that David Gockley makes more than a million dollars a year, most recent the claim that his base salary is $1.2 million. Folks, this is just not true. His base salary, as shown by some years of 990s, is currently around $525,000. The most recently filed 990 shows that Gockley received a one-time bonus of $1 million.
I went into some detail in SFCV a couple of weeks ago about why I believe he earned and deserves every penny of that bonus. I'm not happy about the failure of other people reporting on this subject to get his compensation right. A half-million dollar salary is reasonable for running a complicated organization with a $70 million annual budget. Misrepresenting his earnings because you didn't do enough research is not reasonable.