Reverse line movements lead to big profits

Every week, regardless of the sport, head-scratching upsets take place that have bettors cursing the heavens and crying foul while ripping up there tickets.

For example, how could the lowly Miami Dolphins of the NFL beat a San Diego Chargers team than many predicted to go to the Super Bowl outright? Or how could a terrible Michigan football team upset a Wisconsin club that was expected to challenge for the Big Ten title?

Well, both of these games had something in common that shrewd bettors could have used to their advantage, and that could have made these upsets both expected and profitable. Welcome to the world of reverse line movement.
\
Reverse line movement takes place when a large majority of bets are on one team, yet the line moves in the opposite direction. For example, in the two cases above, at least 75 percent of all bets were placed on the Chargers and Wisconsin respectively. Yet, the Chargers line dropped from an opener of -7 to a closing line of -5½, while Wisconsin fell from -6½ to -5. You all now know what transpired on the field on each occasion.

So what causes reverse line movement when the aim of most bookmakers is to get as close to balanced action on both sides as possible? The answer to this is quite simple: the sharp bettors. You see, reverse movement takes when more money is bet by the small percentage of bettors that are on the unpopular side (the sharps) than is bet by the huge majority of players betting the popular side (the squares). Thus, following reverse line movements is the same thing a following the smart money.

Now do the sharps win every single time? Absolutely not! However, they are right more often than they are wrong, so being on the same side as the sharps is a prudent strategy over the long run.

To back this up, our friends over at Sports Insights have tracked the records for games where over 60 percent of the public has been on one side, yet there was reverse line movement of at least one full point from the opening number to the close at the top books in NFL, NCAAF, NBA and NCAAB. As you can see, this strategy has been profitable in every sport. Note that these records are for sides only and do not include totals.


At Least 60% of Bets on Side, Reverse Line Move of at least 1 point
League W L P Pct Units
NFL 2008 18 13 1 58.1% 2.83
NFL 2007 155 130 9 54.4% 18.62
NCAAF 2008 137 106 8 56.4% 17.51
NCAAF 2007 227 156 4 59.3% 49.49
NBA 2007-8 221 182 6 54.8% 18.89
NCAAB 2007-8 272 203 11 57.3% 42.04


Also, games where over 60 percent of the public are on one side, yet there is reverse line movement of at least 10 cents on the Money Line from the opening number to the close at the top books in MLB and NHL has also been profitable. Again, these records are for money lines only and do not include totals.


At Least 60% of Bets on Side, Reverse Money Line Move of at least 10 cents
League W L P Pct Units
MLB 2008 518 600 0 46.3% 131.98
NHL 2008-9 1 0 0 100.0% 0.95
NHL 2007-8 224 229 0 49.4% 85.69


Obviously, this approach produces a lot of underdog money line plays, as you can see by comparing the winning percentages in MLB and NHL with the units won. However, one cannot quibble with the results, and dare we say, this is an approach that makes money in the long run without doing any handicapping.