How are the lines set?

While the odds makers do to try approximate the median margin of victory between two teams, they also try to reduce their exposure to risk by setting lines such that the public money will fall evenly on both sides of a game, so that they can offset the bets against each other and earn a profit on the juice (cut of winnings taken by the house, explained below) without exposing themselves to large potential losses. Thus, odds makers are often in the business of gauging public perception rather than team performance, and therefore the betting public actually sets the line. If Georgia is 4 points better than Georgia Tech according to my advanced metrics and analysis, but the aggregate public perception is that Georgia is 7 points better than Georgia Tech, then the posted point spread is likely to be closer to 6.5 or 7 points (public perception) than it will be to 4 points (the realistic difference between the teams). This makes my job as a professional handicapper much less daunting; not only can I exploit lines where the odds makers leave an edge, but I can also exploit the uniformed opinions of the general betting public.

Isn't gambling risky?

I don't believe that the term 'gambling' applies to what I do. I sell information to subscribers, with which they can take positive expectation positions in uncertain markets. With correct financial optimization and bankroll management, long term risks are nominal compared to the risks of investing in other, more conventional markets. Just as a single stock may go up or down in a day, any one team may win or lose a given game. But as long as the investor maintains a long-term perspective, understands variance, and doesn't over-extend themselves or bet more than they can easily handle, risk can be highly mitigated, and they can earn a very attractive risk adjusted return.