JoeyOh
02-19-2006, 12:14 AM
I came across this study... thought it was neat
NFL Line Movement Analysis:
The results of a 6 year study on NFL point spread moves.
My biggest questions have been: What line is best for my TER and Team Momentum calculations—opening... closing... something in-between? And, to a lesser extent: Is there an edge to be had by betting a certain side, at a certain time of the week, after a spread has moved in one particular direction?
Because the point spread is factored directly into my formula used to isolate "Soft Line Advantages", and subsequently plugged directly into my Team Momentum grid—a grid that can produce two totally different results even with a shift in the point spread of only ½ point—it became clear to me in the early part of 2005 that some heavy duty research on the historical patterns of NFL line moves was in order. As I mentioned above, my goal was to not only better reconcile the usage of different lines taken from various days of the week, within the framework of my overall methodology, but to also help the general bettor trying to improve their timing of wagers. Now, before I get to my findings—some background on the history of the point spread itself.
While various civilizations and cultures around the world have been engaged in some form of betting for more than 3000 years, the point spread, or "betting line", is a relatively new invention and has only been in use for the better part of 70 years. It's impact in this relatively short period of time is undeniable and as an un-named bookie quoted in a 1951 book by sports journalist Charles Rosen put it: The spread has easily been "the greatest discovery since the Zipper". Without question, it has had a huge part to play in today's popularity of one sport in particular—the National Football League.
While most certainly an American invention, the true origin of the point spread is cloudy. Some experts believe it was introduced in the 1920's while others claim it wasn't widely used until the 1930's in the New York area. Regardless of it's actual birth-date, this much is known—In the years following the 2nd world war, the point spread became the dominant form of wagering for both American football and basketball. It was a bookies dream, helping to make the underdog much more attractive and assuring sports books and bookies a 10% profit on the "vigorish" shaved off the top of winning bets.
Originally set in the early days by a consulting firm out of Minneapolis run by Leo Hirschfield, spreads are now more of a consensus originated by managers from sports books inside Vegas' casino's; at online books; as well as offshore establishments. For the purposes of my research, I have relied on the lines provided by the Don Best Sports Information Service, a consensus of roughly 25 sportsbooks (17 offshore and 8 Las Vegas).
For the majority of games, the point spread is initially set in the hope that wagers will fall fairly evenly on both contestants. Sometimes the bookmakers will misread public opinion and you may see a 2 or 3 point move in the point spread from early in the week until the close of betting action. In other situations, the bookmakers will purposely set a skewed line in an attempt to sucker the public into taking predominately one side—a team that those in the "know" will stay away from. While this might appear to be a risky position for the sport books to take, having 90% of action on one side where the line value greatly favours the bookmaker is a good situation for sports books (and individual bookies) to be in over the long-haul.
The Internet age has certainly helped to sharpen the betting skills of the average bettor by providing an abundance of high level handicapping info. But, despite the wealth of decent information available, a large percentage of bettors can still be classed as "squares"—meaning, they will bet on the well-known favorites week after week, no matter what the circumstances. It's this group of novice and intermediate bettors that Vegas and the off shore books will prey on over the course of each season. Using services that track where square money is flowing each week, sharper bettors can put themselves in a position to "cash-in" on sucker lines and play against the majority. This is a strategy that works very well in some years (though not all).
Now, getting back to my research—As I have discovered, the weekly dance between those who set the line, and the thousands upon thousands of bettors who subsequently move it in different directions, can lend real insight into which team will end up covering the number.
Using data from Week 10 of 1998 up until the end of the 2004 season, I analyzed line movements that occurred between Wednesday evening and approximately ½ hour before game time. I picked ½ hour before game time as my ending value to avoid any wild fluctuations that can occur in the short few minutes leading up to game time. These ultra-late line moves don't really have any handicapping value considering the limited amount of time one has to act on them even if an edge were to be had. Wednesday is when my analysis is first sent out (mostly to accomodate office pool players) so it seemed like a good idea to use this line as my starting point. This is not the only reason I chose Wednesday as my starting point, but more on that later.
The first thing I wanted to know was—what general direction do line moves usually take? And, how often were there no changes at all? Here is what I found:
42.6% of the time, the line posted ½ hour before game time will be the same line that was posted on Wednesday evening. This is not to say that the line did not fluctuate at any time in-between, only that the Wednesday evening and Sunday near-closing line were the same.
31.9% of the time, the team that was favoured on Wednesday evening will be a bigger favourite ½ hour before game time.
Finally, 25.5% of the time, the team that was favoured on Wednesday evening will be a smaller favourite ½ hour before game time (or their opponent will have become the favourite—still a move in the same direction).
These numbers would appear to back up the long-standing rule that it is better to bet favourites early in the week and underdogs later in the week because as more and more "squares" start making their bets, the lines for favorites will get bigger, making the underdog more attractive as the week progresses. This can be shown by the fact that lines tend to increase almost 6% more than they decrease between Wednesday evening and ½ prior to game time.
This is an important consideration when trying to time a wager to achieve the most advantageous line possible (e.g., its better to take St. Louis -13.5 on Wednesday, than St. Louis -14 on Sunday for obvious reasons). But, can we further analyze line movement data to find an edge that goes well beyond the few extra wins we might eke out based on timing alone?
The next stage of my line movement research involved tabulating the actual ATS records of 4 different betting situations, all with one common theme—the line posted Wednesday evening and ½ hour before game time was different. A description of the situations and an example of each is listed below:
#1 Betting on a favourite on Wednesday night after which the line increases in size (Wager: Chicago -7 @ Wednesday 6pm— ½ hour prior to game time Chicago is -8.5).
#2 Betting on a favourite ½ hour before game time where the line increased from Wednesday night (Wager: Chicago -8.5 @ ½ hour before game time—Wednesday 6pm Chicago was -7).
#3 Betting on an underdog on Wednesday night after which the line decreases in size, or the team in question becomes the favourite. (Wager: Chicago +1 @ Wednesday 6pm— ½ hour before game time Chicago is -1).
#4 Betting on the team that was the underdog Wednesday night, ½ hour prior to game time, as long as the line decreased from Wednesday night, or the team in question became the favourite. (Wager: Chicago +4.5 @ ½ hour before game time—Wednesday 6pm Chicago was +5.5).
Situations 1 and 2 are really the same wager, just at different times of the week with slightly different point spreads, while the same goes for Situations 3 and 4. So, how did the teams in the above situations perform against the spread? See for yourself:
#1 262-235 ATS—52.7% (42-38 in '04)
#2 251-250 ATS—50.1% (42-39 in '04)
#3 239-186 ATS—56.2% (38-34 in '04)
#4 230-195 ATS—54.1% (38-35 in '04)
Well, what should we make of these records?
Situation 1 and 2.
Betting on favourites where the spread increases between Wednesday evening and ½ hour before game time is not a great wager at either end. The only lesson to be learned here is that, if you are positive that you want to side with a favourite on Wednesday night, and you have a strong feeling that the spread might increase before game time, you are well advised to place your wager on Wednesday (262 wins compared with 251 when betting shortly before game time). This again is further proof that it is often better to wager on favourites earlier in the week.
Situation 3 and 4.
Betting on underdogs where the spread decreases between Wednesday evening and ½ hour before game time is actually a very good wager, especially if you have an idea that an underdog is set to move in this direction on Wednesday evening (you would have been a whopping 239-186 ATS in the past 6 years if you correctly predicted this situation each time). While Situations 3 and 4 occur far less than Situations 1 and 2, they are far more profitable and deserve attention from the bettor looking to cash in on line movements.
Now, you might be ready to ask me: How can I really tell if a line is going to increase or decrease in-between Wednesday evening and shortly before game time? If we know this ahead of time both for Situation 1 and 2 for example, we could actually show a small profit by betting on favourites on Wednesday night, when the line increases thereafter. In hindsight it seems fairly simple, but getting that 52.7% winning percentage means being able to accurately predict the direction that the line will move later in the week. Can these movements be predicted with any great accuracy or are we left to make only an educated guess?
You might remember that part of the reason I made the Wednesday evening line my starting point was because this is when I first send out my selections each week. Also, most games have a stable line posted by Wednesday evening thereby allowing my TER and Team Momentum methods—which rely entirely on the point spread—the opportunity to produce an accurate assessment of each game.
Using the Wednesday line also gives me the luxury of already having up to 72 hours of previous line movement data to work with. Suddenly, Wednesday is not really a starting point, but more the middle point of a data set consisting of three measurements taken at different stages of the week.
Many games actually have a line posted as early as Sunday evening or Monday morning. Often, lines will move the most in the short hours after they open when a large number of bettors place wagers on one side in particular. Does the line movement that may occur between the time a line opens, and Wednesday evening, foretell where a line might move later in the week?
The answer is a resounding yes. I won't drill down into all the data here (this article is getting long enough). But, suffice it to say that: roughly 80% of the time, line moves that occur between Wednesday evening and ½ hour prior to game time will follow the same direction as movement that occurred between opening and Wednesday evening.
So, a favourite that opens at -10 and is quickly bet to -11.5, will stay at -11.5 or become an even bigger favourite 80% of the time (using the line ½ hour before game time as the final measurement). This also holds true for favourites that trend smaller as well. A team that opens at -7 and is -6.5 by Wednesday evening, will stay at -6.5 or move to -6 or lower, roughly 80% of the time.
Knowledge of the above similarities between early, and mid-to-late week line movements can help you flag games with lines that should have a tendency to move in the direction you want, but this particular trend falls short of guaranteeing that the line will in fact, move at all. The parallels between early and mid-to-late week line changes really show their worth in the final section of my line movement analysis which is coming up below.
So, to the bettor that simply wants to wager based on a strategy revolving around line movement I say this: Don't bother betting on games where the public likes the favourite and the line has increased from the time it opened. There is scant money to be made on these games. Do bet on underdogs that the public likes and have been bet to such an extent that the amount of points they are getting has decreased between Wednesday night and ½ hour prior to game time. Keep your eye on any games that show line movement early in the week in this direction and at the slightest hint of any further moves after Wednesday evening, put your money on the dog. In most cases the line will not back track. To be completely safe, you could wait until ½ hour prior to game time to ensure that the line remains lower than it was Wednesday night. Even at this point, you will still have a 54.1% chance of covering the spread, based on results since 1998.
Late Line Change Bulletins
This is the portion of my point-spread research that will be of most interest to my current or potential subscribers—the analysis of how line movements actually fit into my handicapping methodology and how these line changes may affect my Wednesday selections. If you are jumping into the article at this particular point you may want to back track to the top for some additional background information.
Now, before we get started, I must offer up the following warning to those subscribers who are keen on charting their own line moves for use within the confines of my handicapping system:
DO NOT TRY THIS AT HOME
What your local bookie or online sportsbook is doing with their lines in the run-up before game-time may not neccessarily match the current data obtained from my sources. So, unless you receive a Late Line Change Bulletin email from me, my Wednesday selections will NOT change and neither should yours, regardless of the lines that you might encounter. And now, back to the article....
Without question, the point spread is easily the most important piece of information that my handicapping methodology relies on. Used in conjunction with my Team Efficiency Ratings (TER's), it enables me to calculate a games Soft Line Advantage measurement, which is then, in turn, used to formulate a Team Momentum rating.
So, not only is my Team Momentum rating dependant on the fundamental and situational factors that surround each game, but it is also directly influenced by how the betting public perceives both teams—a view which is quantified via the point spread.
Even a change of ½ point to the line can shift a team from a positive Team Momentum situation, into a negative one, thereby necessitating a change in my selection for that game. Luckily enough, my research on point-spread moves from the past 6 years has uncovered a clear pattern revealing what particular lines (i.e., Wednesday, Sunday, etc.) work best with my system, after the direction of these moves are taken into consideration.
There are only 2 different situations that we need to take into account for the purposes of this exercise and they are:
A) The line increases between Wednesday evening and ½ hour prior to game time. Or,
B) The line decreases between Wednesday evening and ½ hour prior to game time (or the team that was favoured Wednesday night becomes the underdog).
Now, just to state the obvious—if my pick on a Wednesday night is Seattle -7 points, and the line remains at this number ½ hour before game time, then my pick will remain the same. No surprise there.
For games where the line increases between Wednesday evening and ½ hour prior to game time (Scenario A), I have found that, for the most part, my TER algorithm and subsequent Team Momentum measurements are more effective when using the Wednesday evening line for their calculations. This is good news for office poolies who rely on my Wednesday selections or those bettors who don't want to wait until the last minute to place a wager.
There is actually one instance in Scenario A, where I do not want to use the Wednesday line, and this occurs when the near-closing line ends up at 10 points or greater. When a big favourite on Wednesday, gets even bigger nearer to game time, I have much better success by taking this late movement into account, and plugging the near-closing line into my algorithm. In all other cases where the line increases, the Wednesday number is more effective.
For games where the line shrinks for the favourite between Wednesday evening and ½ hour prior to game time, or the favourite becomes the underdog (Scenario B), my system has been shown to be far more effective when using the line posted ½ hour prior to game time to base it's calculations on. It's games that fall into this situation—along with big favourites that trend even bigger—that may need to be updated via email, once the near-closing line has been established.
Again, by looking at how a line reacts between the time it opens, and Wednesday night, I can predict with a fair degree of accuracy, the direction that any further moves will take between Wednesday night and ½ hour prior to game time. So, I can be fairly safe in assuming that a line that went from -7 to -7.5 in the early stages of the week, will either stick at -7.5, or move to -8 or higher, roughly 80% of the time. In these cases my Wednesday pick is fairly solid.
If a line were to open at -3, and remained at -3 Wednesday evening, I could also be fairly confident in this situation that the line will still be at -3 @½ hour prior to game time. Numbers on common margins of victory (i.e. 3, 7) move far less than other lines.
For games where there has been no early movement (Monday-Tuesday) and the number is well off of a common margin of victory (i.e. -5.5, -1.5). Or, games where the line has already shrunk shortly after opening—these are the situations where I will hold off on making a concrete selection on Wednesday.
Considering that Scenario B only occurs 25.5% of the time (I covered this stat a little earlier in this article), and only about half of these cases will find a different result after my Team Momentum rating is re-calculated using the later line—this effectively means that I will only need to alter my Wednesday selection about 10-15% of the time (or roughly 2 games per week when all teams are playing). These are the games that my subscribers will receive an email on approximately ½ hour prior to game time (normally 12:30, 3:30, and 8:00 PM on Sunday, and 8:30PM on Monday). These emails are otherwise known as a Late Line Change Bulletins.
This all sounds like a lot of hassle. But, by doing this, I have calculated that I should be able to squeeze another 4-5 wins out of a typical season which equates to a 2% boost in winning percentage, based on 207 selections.
Ultimately, I hope that I have finally put to bed the big question of which line works best for my analysis. This is good news for my subscribers considering the amount of time I have wasted writing about this topic over the past few years and the endless flip-flopping of email timings as well. This begs another question however—what the heck am I supposed to research now? Well, I'm sure I will find something else to keep me busy. ;)
NFL Line Movement Analysis:
The results of a 6 year study on NFL point spread moves.
My biggest questions have been: What line is best for my TER and Team Momentum calculations—opening... closing... something in-between? And, to a lesser extent: Is there an edge to be had by betting a certain side, at a certain time of the week, after a spread has moved in one particular direction?
Because the point spread is factored directly into my formula used to isolate "Soft Line Advantages", and subsequently plugged directly into my Team Momentum grid—a grid that can produce two totally different results even with a shift in the point spread of only ½ point—it became clear to me in the early part of 2005 that some heavy duty research on the historical patterns of NFL line moves was in order. As I mentioned above, my goal was to not only better reconcile the usage of different lines taken from various days of the week, within the framework of my overall methodology, but to also help the general bettor trying to improve their timing of wagers. Now, before I get to my findings—some background on the history of the point spread itself.
While various civilizations and cultures around the world have been engaged in some form of betting for more than 3000 years, the point spread, or "betting line", is a relatively new invention and has only been in use for the better part of 70 years. It's impact in this relatively short period of time is undeniable and as an un-named bookie quoted in a 1951 book by sports journalist Charles Rosen put it: The spread has easily been "the greatest discovery since the Zipper". Without question, it has had a huge part to play in today's popularity of one sport in particular—the National Football League.
While most certainly an American invention, the true origin of the point spread is cloudy. Some experts believe it was introduced in the 1920's while others claim it wasn't widely used until the 1930's in the New York area. Regardless of it's actual birth-date, this much is known—In the years following the 2nd world war, the point spread became the dominant form of wagering for both American football and basketball. It was a bookies dream, helping to make the underdog much more attractive and assuring sports books and bookies a 10% profit on the "vigorish" shaved off the top of winning bets.
Originally set in the early days by a consulting firm out of Minneapolis run by Leo Hirschfield, spreads are now more of a consensus originated by managers from sports books inside Vegas' casino's; at online books; as well as offshore establishments. For the purposes of my research, I have relied on the lines provided by the Don Best Sports Information Service, a consensus of roughly 25 sportsbooks (17 offshore and 8 Las Vegas).
For the majority of games, the point spread is initially set in the hope that wagers will fall fairly evenly on both contestants. Sometimes the bookmakers will misread public opinion and you may see a 2 or 3 point move in the point spread from early in the week until the close of betting action. In other situations, the bookmakers will purposely set a skewed line in an attempt to sucker the public into taking predominately one side—a team that those in the "know" will stay away from. While this might appear to be a risky position for the sport books to take, having 90% of action on one side where the line value greatly favours the bookmaker is a good situation for sports books (and individual bookies) to be in over the long-haul.
The Internet age has certainly helped to sharpen the betting skills of the average bettor by providing an abundance of high level handicapping info. But, despite the wealth of decent information available, a large percentage of bettors can still be classed as "squares"—meaning, they will bet on the well-known favorites week after week, no matter what the circumstances. It's this group of novice and intermediate bettors that Vegas and the off shore books will prey on over the course of each season. Using services that track where square money is flowing each week, sharper bettors can put themselves in a position to "cash-in" on sucker lines and play against the majority. This is a strategy that works very well in some years (though not all).
Now, getting back to my research—As I have discovered, the weekly dance between those who set the line, and the thousands upon thousands of bettors who subsequently move it in different directions, can lend real insight into which team will end up covering the number.
Using data from Week 10 of 1998 up until the end of the 2004 season, I analyzed line movements that occurred between Wednesday evening and approximately ½ hour before game time. I picked ½ hour before game time as my ending value to avoid any wild fluctuations that can occur in the short few minutes leading up to game time. These ultra-late line moves don't really have any handicapping value considering the limited amount of time one has to act on them even if an edge were to be had. Wednesday is when my analysis is first sent out (mostly to accomodate office pool players) so it seemed like a good idea to use this line as my starting point. This is not the only reason I chose Wednesday as my starting point, but more on that later.
The first thing I wanted to know was—what general direction do line moves usually take? And, how often were there no changes at all? Here is what I found:
42.6% of the time, the line posted ½ hour before game time will be the same line that was posted on Wednesday evening. This is not to say that the line did not fluctuate at any time in-between, only that the Wednesday evening and Sunday near-closing line were the same.
31.9% of the time, the team that was favoured on Wednesday evening will be a bigger favourite ½ hour before game time.
Finally, 25.5% of the time, the team that was favoured on Wednesday evening will be a smaller favourite ½ hour before game time (or their opponent will have become the favourite—still a move in the same direction).
These numbers would appear to back up the long-standing rule that it is better to bet favourites early in the week and underdogs later in the week because as more and more "squares" start making their bets, the lines for favorites will get bigger, making the underdog more attractive as the week progresses. This can be shown by the fact that lines tend to increase almost 6% more than they decrease between Wednesday evening and ½ prior to game time.
This is an important consideration when trying to time a wager to achieve the most advantageous line possible (e.g., its better to take St. Louis -13.5 on Wednesday, than St. Louis -14 on Sunday for obvious reasons). But, can we further analyze line movement data to find an edge that goes well beyond the few extra wins we might eke out based on timing alone?
The next stage of my line movement research involved tabulating the actual ATS records of 4 different betting situations, all with one common theme—the line posted Wednesday evening and ½ hour before game time was different. A description of the situations and an example of each is listed below:
#1 Betting on a favourite on Wednesday night after which the line increases in size (Wager: Chicago -7 @ Wednesday 6pm— ½ hour prior to game time Chicago is -8.5).
#2 Betting on a favourite ½ hour before game time where the line increased from Wednesday night (Wager: Chicago -8.5 @ ½ hour before game time—Wednesday 6pm Chicago was -7).
#3 Betting on an underdog on Wednesday night after which the line decreases in size, or the team in question becomes the favourite. (Wager: Chicago +1 @ Wednesday 6pm— ½ hour before game time Chicago is -1).
#4 Betting on the team that was the underdog Wednesday night, ½ hour prior to game time, as long as the line decreased from Wednesday night, or the team in question became the favourite. (Wager: Chicago +4.5 @ ½ hour before game time—Wednesday 6pm Chicago was +5.5).
Situations 1 and 2 are really the same wager, just at different times of the week with slightly different point spreads, while the same goes for Situations 3 and 4. So, how did the teams in the above situations perform against the spread? See for yourself:
#1 262-235 ATS—52.7% (42-38 in '04)
#2 251-250 ATS—50.1% (42-39 in '04)
#3 239-186 ATS—56.2% (38-34 in '04)
#4 230-195 ATS—54.1% (38-35 in '04)
Well, what should we make of these records?
Situation 1 and 2.
Betting on favourites where the spread increases between Wednesday evening and ½ hour before game time is not a great wager at either end. The only lesson to be learned here is that, if you are positive that you want to side with a favourite on Wednesday night, and you have a strong feeling that the spread might increase before game time, you are well advised to place your wager on Wednesday (262 wins compared with 251 when betting shortly before game time). This again is further proof that it is often better to wager on favourites earlier in the week.
Situation 3 and 4.
Betting on underdogs where the spread decreases between Wednesday evening and ½ hour before game time is actually a very good wager, especially if you have an idea that an underdog is set to move in this direction on Wednesday evening (you would have been a whopping 239-186 ATS in the past 6 years if you correctly predicted this situation each time). While Situations 3 and 4 occur far less than Situations 1 and 2, they are far more profitable and deserve attention from the bettor looking to cash in on line movements.
Now, you might be ready to ask me: How can I really tell if a line is going to increase or decrease in-between Wednesday evening and shortly before game time? If we know this ahead of time both for Situation 1 and 2 for example, we could actually show a small profit by betting on favourites on Wednesday night, when the line increases thereafter. In hindsight it seems fairly simple, but getting that 52.7% winning percentage means being able to accurately predict the direction that the line will move later in the week. Can these movements be predicted with any great accuracy or are we left to make only an educated guess?
You might remember that part of the reason I made the Wednesday evening line my starting point was because this is when I first send out my selections each week. Also, most games have a stable line posted by Wednesday evening thereby allowing my TER and Team Momentum methods—which rely entirely on the point spread—the opportunity to produce an accurate assessment of each game.
Using the Wednesday line also gives me the luxury of already having up to 72 hours of previous line movement data to work with. Suddenly, Wednesday is not really a starting point, but more the middle point of a data set consisting of three measurements taken at different stages of the week.
Many games actually have a line posted as early as Sunday evening or Monday morning. Often, lines will move the most in the short hours after they open when a large number of bettors place wagers on one side in particular. Does the line movement that may occur between the time a line opens, and Wednesday evening, foretell where a line might move later in the week?
The answer is a resounding yes. I won't drill down into all the data here (this article is getting long enough). But, suffice it to say that: roughly 80% of the time, line moves that occur between Wednesday evening and ½ hour prior to game time will follow the same direction as movement that occurred between opening and Wednesday evening.
So, a favourite that opens at -10 and is quickly bet to -11.5, will stay at -11.5 or become an even bigger favourite 80% of the time (using the line ½ hour before game time as the final measurement). This also holds true for favourites that trend smaller as well. A team that opens at -7 and is -6.5 by Wednesday evening, will stay at -6.5 or move to -6 or lower, roughly 80% of the time.
Knowledge of the above similarities between early, and mid-to-late week line movements can help you flag games with lines that should have a tendency to move in the direction you want, but this particular trend falls short of guaranteeing that the line will in fact, move at all. The parallels between early and mid-to-late week line changes really show their worth in the final section of my line movement analysis which is coming up below.
So, to the bettor that simply wants to wager based on a strategy revolving around line movement I say this: Don't bother betting on games where the public likes the favourite and the line has increased from the time it opened. There is scant money to be made on these games. Do bet on underdogs that the public likes and have been bet to such an extent that the amount of points they are getting has decreased between Wednesday night and ½ hour prior to game time. Keep your eye on any games that show line movement early in the week in this direction and at the slightest hint of any further moves after Wednesday evening, put your money on the dog. In most cases the line will not back track. To be completely safe, you could wait until ½ hour prior to game time to ensure that the line remains lower than it was Wednesday night. Even at this point, you will still have a 54.1% chance of covering the spread, based on results since 1998.
Late Line Change Bulletins
This is the portion of my point-spread research that will be of most interest to my current or potential subscribers—the analysis of how line movements actually fit into my handicapping methodology and how these line changes may affect my Wednesday selections. If you are jumping into the article at this particular point you may want to back track to the top for some additional background information.
Now, before we get started, I must offer up the following warning to those subscribers who are keen on charting their own line moves for use within the confines of my handicapping system:
DO NOT TRY THIS AT HOME
What your local bookie or online sportsbook is doing with their lines in the run-up before game-time may not neccessarily match the current data obtained from my sources. So, unless you receive a Late Line Change Bulletin email from me, my Wednesday selections will NOT change and neither should yours, regardless of the lines that you might encounter. And now, back to the article....
Without question, the point spread is easily the most important piece of information that my handicapping methodology relies on. Used in conjunction with my Team Efficiency Ratings (TER's), it enables me to calculate a games Soft Line Advantage measurement, which is then, in turn, used to formulate a Team Momentum rating.
So, not only is my Team Momentum rating dependant on the fundamental and situational factors that surround each game, but it is also directly influenced by how the betting public perceives both teams—a view which is quantified via the point spread.
Even a change of ½ point to the line can shift a team from a positive Team Momentum situation, into a negative one, thereby necessitating a change in my selection for that game. Luckily enough, my research on point-spread moves from the past 6 years has uncovered a clear pattern revealing what particular lines (i.e., Wednesday, Sunday, etc.) work best with my system, after the direction of these moves are taken into consideration.
There are only 2 different situations that we need to take into account for the purposes of this exercise and they are:
A) The line increases between Wednesday evening and ½ hour prior to game time. Or,
B) The line decreases between Wednesday evening and ½ hour prior to game time (or the team that was favoured Wednesday night becomes the underdog).
Now, just to state the obvious—if my pick on a Wednesday night is Seattle -7 points, and the line remains at this number ½ hour before game time, then my pick will remain the same. No surprise there.
For games where the line increases between Wednesday evening and ½ hour prior to game time (Scenario A), I have found that, for the most part, my TER algorithm and subsequent Team Momentum measurements are more effective when using the Wednesday evening line for their calculations. This is good news for office poolies who rely on my Wednesday selections or those bettors who don't want to wait until the last minute to place a wager.
There is actually one instance in Scenario A, where I do not want to use the Wednesday line, and this occurs when the near-closing line ends up at 10 points or greater. When a big favourite on Wednesday, gets even bigger nearer to game time, I have much better success by taking this late movement into account, and plugging the near-closing line into my algorithm. In all other cases where the line increases, the Wednesday number is more effective.
For games where the line shrinks for the favourite between Wednesday evening and ½ hour prior to game time, or the favourite becomes the underdog (Scenario B), my system has been shown to be far more effective when using the line posted ½ hour prior to game time to base it's calculations on. It's games that fall into this situation—along with big favourites that trend even bigger—that may need to be updated via email, once the near-closing line has been established.
Again, by looking at how a line reacts between the time it opens, and Wednesday night, I can predict with a fair degree of accuracy, the direction that any further moves will take between Wednesday night and ½ hour prior to game time. So, I can be fairly safe in assuming that a line that went from -7 to -7.5 in the early stages of the week, will either stick at -7.5, or move to -8 or higher, roughly 80% of the time. In these cases my Wednesday pick is fairly solid.
If a line were to open at -3, and remained at -3 Wednesday evening, I could also be fairly confident in this situation that the line will still be at -3 @½ hour prior to game time. Numbers on common margins of victory (i.e. 3, 7) move far less than other lines.
For games where there has been no early movement (Monday-Tuesday) and the number is well off of a common margin of victory (i.e. -5.5, -1.5). Or, games where the line has already shrunk shortly after opening—these are the situations where I will hold off on making a concrete selection on Wednesday.
Considering that Scenario B only occurs 25.5% of the time (I covered this stat a little earlier in this article), and only about half of these cases will find a different result after my Team Momentum rating is re-calculated using the later line—this effectively means that I will only need to alter my Wednesday selection about 10-15% of the time (or roughly 2 games per week when all teams are playing). These are the games that my subscribers will receive an email on approximately ½ hour prior to game time (normally 12:30, 3:30, and 8:00 PM on Sunday, and 8:30PM on Monday). These emails are otherwise known as a Late Line Change Bulletins.
This all sounds like a lot of hassle. But, by doing this, I have calculated that I should be able to squeeze another 4-5 wins out of a typical season which equates to a 2% boost in winning percentage, based on 207 selections.
Ultimately, I hope that I have finally put to bed the big question of which line works best for my analysis. This is good news for my subscribers considering the amount of time I have wasted writing about this topic over the past few years and the endless flip-flopping of email timings as well. This begs another question however—what the heck am I supposed to research now? Well, I'm sure I will find something else to keep me busy. ;)