Comping rates

What is the percentage of what the casinos expect to win do they return in comps.

At table games like blackjack, most casinos generally assume they will win at 2% rate. The classic formula is to give back 40% of that gain as comps. So, on $5000 worth of action, the casinos figure you will lose (and they will gain) $100. So you can expect a comp worth $40. Low green action will get you great comps downtown and on some strip properties, like the Stardust.
From what I can tell, however, more expensive and sophisticated properties, like the MGM hotels, appear to base their comp formulas much closer to the EV on basic strategy. It takes low black to get the goodies at these carpet joints.

OK, but is there a site where I can get the EXACT percentage for the returns? I need the specifics for a project. Thanks.

The 40% rule comes from postings on this page, plus a number of books on the subject of gambling and comps. Jean Scott's "The Frugal Gambler" (pp. 35-38) has charts showing both standardized measure and casino advantage for most slots and table games. From there, every casino has its own comp policy, but with a little research you might be able to reverse engineer their formulas. You might start at the link below. The Stardust posts their comp requirements on-line for all to see. You can calculate the value of these comps based on published room rates, typical meal costs, airfare and so on. Other casinos might post their requirements, or a host might gladly discuss them with you. But I don't know if there is any "master chart" for the industry. Please also note that many comps, especially low level buffet and coffee shop comps, can be discretionary for the PB. If you find any surprising information about comp policies among LV hotels, let us know.