The "Avg. Rakeback" for each site is equal to the average rakeback for players who generate between $1,000 to $100,000 per year in rake and fees. This calculation does not include players who generate <$1,000/year in rake and fees because these players can often earn well over 100% rakeback due to freerolls. Since we have included freeroll value as a separate entry, including these players would heavily skew the results in favor of sites that offer high value freerolls to low limit players.
The "Avg. Rakeback" numbers presented in the above tables are just a general reflection of each site's commitment to rakeback and are not indicative of how much you will necessarily earn. Rakeback rewards are highly dependent on a number of factors including volume of play, preferred game type, etc. If rakeback is your primary concern, you should instead use our poker site rankings tables, which compare online poker sites by total net cost (rake/fees - rewards).