Categories and Correlations - Part 3

...Continuing from Categories and Correlations - Part 2 (Please read that post first)

There are 126 different groups of 5 categories. Each group of 5 is defined by the 10 relationships between its variables. For example, if we pick categories A,B,C,D, and E, then we need to look at the correlations: 1. A vs. B, 2. A vs. C, 3. A vs. D, 4. A vs. E, 5. B vs. C, 6. B vs. D, 7. B vs. E, 8. C vs. D, 9. C vs. E, and 10. D vs. E

The strength of how well 5 categories work together is defined as the average of these 10 correlations. I ranked the 126 possible groups of 5 categories on this average correlation. The average correlation of the 126 possible groups ranges from -.15 to .49. Any average below 0 means a player who's good at any one of the 5 categories is likely to be bad at the remaining 4. The group of 5 at the top of the list, the one with an average of .49 is quite special, b/c not only does it have the best average correlation (best by a large margin, #2 has an average of .41), but it is the only 1 in 126 where none of the 10 correlations between the 5 categories are negative. All 10 are nicely positive, the minimum of the 10 correlations is .27. The 5 best categories to go for are: FT%, 3 Pointers Made, Points, Assists, and Steals.

So that's it for categories and correlations. You now know which 5 categories around which to build a team.

Categories and Correlations - Part 2

...Continuing from Categories and Correlations - Part 1 (Please read that post first)

First, a necessary note on turnovers: From now on turnovers will refer to the opposite of turnovers. In the last post we saw that points and turnovers had a very strong correlation. if we use the opposite of turnovers, then points and turnovers become strongly negatively correlated. For the purposes of determining which categories to go for, strong correlations will now always be a good thing and negative correlations will now always be a bad thing.

There are 9 categories and there are 36 unique pairs of categories. We have 36 category to category correlations to analyze. The 2 scatter plots in the previous post show the category to category relationships for 2 of these 36 combinations. I won't show any more scatter plots, but here are the correlation coefficients for all 36 possible pairs of categories:

The negative relationships are in red and the positive correlations are in black. The 5 highest correlations are (These aren't the strongest correlations, just the strongest positive ones):

• Steals vs. Assists - .70
• Blocks vs. Rebounds - .67
• Steals vs. Points - .64
• Points vs. Asssits - .59
• Points vs. 3 Pointers Made - .53

You might be thinking, "Great let's use those 5 to pick which categories to go after". The above 5 strong correlations involve 6 categories (everything except FG%, FT%, and TO) and as a group of 6, there are many negative correlations between them. (Blocks vs. Assists, Rebounds vs. 3 Pointers, Etc.)

So back to the question of determining which 5 categories to go after.. We can't just look at the correlations between pairs of categories. We need to see how 5 categories can work together.

There are 126 ways to pick 5 categories from the 9. We need to pick the best group of 5 categories from the 126 different possibilities.

To be Continued...

Categories and Correlations - Part 1

Continuing from Fantasy Basketball Introduction... (Please read that post first)

There are 9 categories and you need to pick which 5 to go for. Take a look at this graph showing the points and turnovers from last season for the top 150 fantasy players:

With the exception of Dirk Nowitzki, every player over 2,000 points averaged at least 2 turnovers per game. As you can see from the above graph (and already know from common basketball sense), the players that score a lot of points are also the players that turn the ball over the most. So for starters, if you decide to go for points, you can't go for turnovers. And if you want to make your team good at turnovers, then you can't also try to be good in points.

By the way, points and turnovers have a 0.84 correlation coefficient. If you do not know know what a correlation coefficient is, here's a link to the wikipedia article about them: http://en.wikipedia.org/wiki/Correlation_coefficient

Unlike the strong correlation between points and turnovers, some pairs of the 9 fantasy categories have a strong relationship that can be used to our advantage. For example, here's a scatter plot showing the steals and assists for the top 150 fantasy players:

As you can see, there is a fairly strong positive correlation (As you already knew from basketball common sense). Players that get the most assists also tend to get the most steals.

To be continued...

Fantasy Basketball Introduction

The 2007-2008 NBA season starts on October 30, which means it's time to start thinking about your fantasy draft strategy! My posts will assume you are competing in a head to head league with the standard 9 statistical categories (FG%, FT%, Points, 3-Pointers Made, Rebounds, Assists, Steals, Blocks, and Turnovers) and standard 10 starting position slots (PG, SG, G, SF, PF, F, 2 C, and 2 Util).

Let's assume that you agree with your league's "projected" rankings. The big question is then, on draft day, besides picking the best rated player with each of your picks (and making sure you fill your starting positions), what else can you do gain an edge that will benefit you all season long (and throughout your league's playoffs)?

Some players have a good overall rating because they excel in a single category. Andrei Kirelenko is one such player (He's a blocks machine). If you always pick the best overall player available, you might end up with a team full of players that are only good at a few categories. You'll be destined to lose all your head to head matchups despite dominating your opponents in a few categories.

At the other end of the spectrum, some players have a good overall rating because they are decent in almost all 9 categories. For example, look at Manu Ginobli, Leandro Barbosa, and Teyshaun Prince's stats from 2006-2007; these guys were good in 8 or all 9 categories. If you always pick the best overall players, you might end up good talent in all 9 categories. You might have a decent regular season, but in the playoffs, you might meet a team that excels in 5 categories and is lousy in the other 4. Your team was good all season long in all 9 categories, but this team will likely beat you 5-4 and advance in the playoffs.

You want to be the that kind of team, the team that excels in 5 categories. You might not have the best regular season (and you must accept this). One team might draft to be good at all 9 categories. Against some of the worst teams in the league, that "all around" team might win 9-0 or 8-1. Your team won't be able to beat up on this lousy team, you'll just win 5-4 because unfortunately, b/c you're so good at 5 categories, you're going to be pretty bad at the other 4.

But, when the playoffs come around, and you go to play that "all around" team that won the regular season, you're going to beat them 5-4 and advance in the playoffs.

In my next posts (over the course of the next month). I will show you how to become a team that excels in 5 categories. I'll show you how to decide which 5 of the 9 categories you should go for and then I'll show you how to determine which players will suit your new strategy the best.

Since you will only be aiming to be good at 5 of the categories, the players that fit your team the best will not be the same as the highest overall rated players that every other team is trying to draft. Players that will fit well into your system may be available throughout every round of the draft.

Enjoy, I hope you like it!

Pick Your Running Backs First? - Part 2

My friend/co-worker Rich and I were discussing our upcoming fantasy football draft for our work league (~14 teams). Rich told me that last year every starting RB was taken after the first two rounds (Our league settings are to have 2 RB roster spots per team). In my last post I mentioned that I am going to ignore this common draft plan and pick the best available player with each pick (assuming I have not filled that position yet). I got to worrying because if everyone else picks their running backs first and then some of them pick even more RBs for their bench before I have picked my starting running backs, then the RBs I end up might not be 2 of the best 30 RBs in the league. The graph in my last post only showed the top 30 and I worried that since their are ~30 NFL teams and ~30 starting RBs in the NFL, that the drop-off after rank 30 might be intense. Maybe my last graph failed to capture this. So here's the graph for the top 60 fantasy RBs from last season:


Phewf! There's no severe drop-off after 30. It looks like the best backup RBs in the NFL are nearly worth as many fantasy points as the worst starting RBs. Well, my strategy is reaffirmed. Please let me know if anyone can convince me that I still need to pick my RBs first!

Pick your running backs first?

I saw a fantasy football segment on Sportscenter last night. The analyst advised fantasy drafters to be sure to pick their running backs early on, before the other positions. I figured this must mean that the drop-off in talent at the RB position must be steep compared to QB and WR. I wanted to verify this myself so I calculated the 2006 Fantasy points earned by the top 30 RBs, WRs, and QBs. I graphed the fantasy points versus the position rank to check the "steepness" of the fantasy value dropoff at each position:

I assigned the typical Yahoo fantasy point values:

• QB: 1 pt. / 25 passing yrds + 4 pts / TD minus 1 pt / INT
• RB: 6 pts / TD + 1 pt / 10 rushing yrds
• WR: 6 pts / TD + 1 pt / 10 reception yrds

I can't see what on earth the sportcenter analyst was talking about, there does not seem to be any steep talent drop off with any of the positions. I can tell that the first 10 or so picks are likely to be RBs and QBs, but once the first round goes by, it looks like there should be an equal mix of all 3.

Can anyone explain to me why the analyst advised using your first 2 or 3 picks on running backs? Thanks.

Sit them down!

In all fantasy sports leagues, there are categories with 4 different aims:

• high total (Blocks, Stolen Bases, Touchdown Passes)
• low total (Turnovers, Losses, Flagrant Fouls, Errors)
• high average (Ft %, Slugging %, Pass Completion %)
• low average (ERA, WHIP)

In head to head leagues, you should review your matchup midweek and consider benching some of your players for the rest of the week. For example, in many fantasy baseball leagues, the pitching categories present an opportunity where some active management can help you protect midweek leads. In my baseball leagues, the pitching categories are:

• Wins (high total)
• Losses (low total)
• Saves (high total)
• Strikeouts (high total)
• ERA (low average)
• WHIP (low average)

If midweek you are winning the losses, ERA, and WHIP categories, and you feel that you are unlikely to be passed or pass your opponent in Wins, Strikeouts, or Saves, then you should consider benching your pitchers for the rest of the week.

Catcher

Unless you have Victor Martinez, Russel Martin, Jorge Posada, Brian McCann, or Joe Mauer, you shouldn't be overly satisfied with your catcher. Check to see if anyone in your league has more than one of the catchers in the above list. In my league, one team has Martin and Posada. That same team also has 2 good first basemen occupying the first base and utility spot, leaving either Martin or Posada on his bench each night. I'm going to go after one of his catchers by offering him an improvement over his current utility spot player with some of the extra talent on my bench.

Fantasy Baseball Trade Deadline Approaching

Look for a team in your league that is incredibly bad in one category. Then, see if that team has one player who, unlike the rest of the team, is very good at that one particular category. Make that team an offer for that player. Afterall, the category superstar is adding no value to his current team (he can't win the category all by himself). The manager should be happy to get someone of slightly lesser overall value in return.

Example: My friend Marc's team has only 1 closer (Mariano Rivera). He has only won the saves category one week all season. I point out to Marc that although Mariano Rivera is a dominant closer, he's adding no value to his team. We decide that Mariano is rated the 80th best fantasy player in baseball and Marc is happy to trade him to me for an outfielder ranked 100th.

Welcome

Welcome. My name is Zach. Someday I want to start a fantasy sports consulting company. I have some original, advanced ideas for winning fantasy sports leagues and here I will share them! I appreciate all your comments and feedback.