If you think you know more than the betting market because you watched three games last week, you are making a donation to the sportsbook.
A "market" is efficient when the price reflects all known information. In college basketball, the opening lines might be soft, but by tip-off, the line has been shaped by the sharpest minds and largest bankrolls in the world.
The Closing Line Value (CLV)
The goal is to beat the closing line. If you bet Duke at -4 and the line closes at -6, you've captured 2 points of value. Over thousands of games, this is the only way to overcome the 4.5% vigorish (juice) that sportsbooks charge.