John Grochowski has written a great article on  comp  rates vs expected loss for blackjack, craps and roulette in Gaming and Destinations magazine. I highly recommend reading it.

Here is a brief snippet:

“Blackjack …[$10 wager per hand …  60 hands per hour].  … If the house assumed a 2 percent edge, then it would estimate your theoretical loss at $12. … At a 10 percent comp rate, a casino assuming a 2 percent edge sees an hour of your play as worth $1.20 in comps. If the assumption is a 1 percent edge, an hour’s comps for a $10 player come to only 60 cents.”

Please use the link below to read the full article which goes into further details about our expected loss, what the casino calculates as your theoretical loss, and what comps that may yield.
http://www.gaminganddestinations.com/casino-comps-knowing-the-numbers/