Note that many of the examples used in
these questions and answers refer to games played and seasons prior to 1999.
Although specifics obviously change from season to season, the general
principles regarding the power ratings and their computation and
interpretation do not.
1. How can North Carolina be
ranked 9th with a losing record?
North Carolina played 13 opponents
yielding the fourth toughest schedule. Examining this schedule (see
below), they played seven teams (Virginia twice) that made the
tournament. They beat two of these teams and lost to three others by
one goal, including Princeton which went undefeated. Clearly, North
Carolina was able to stay close with most top ten teams.
Traditionally, polls heavily weigh a victory or loss more than goal
difference or closeness of the score. The power rating credits a
victory in addition to the goal differential but emphasizes the
latter more heavily (although procedures are in place to greatly
minimize the effect of "running up the score").
North Carolina pr = 26.94 rank = 9
opponents ave pr = 25.97 rank = 3
date opponent power score goal difference gain or
rating actual expected loss
222 home vs Butler 22.89 11 5 6 5.71
302 away at Navy 22.41 12 13 -1 2.87 --
308 home vs Loyola 28.76 17 11 6 -0.17 +++
312 away at Duke 31.06 7 8 -1 -5.78 +++
316 home vs Princeton 34.65 9 10 -1 -6.06 +++
322 away at Maryland 29.97 12 13 -1 -4.69 ++
329 home vs Johns Hopkins 32.26 7 15 -8 -3.66 ---
405 away at Virginia 32.86 5 20 -15 -7.59 -----
408 home vs Radford 14.66 16 3 13 13.94
412 home vs Delaware 19.04 21 7 14 9.56 ++
416 home vs VMI 11.60 22 2 20 16.99 +
418 away at Virginia 32.86 13 17 -4 -7.59 ++
503 away at Hofstra 24.55 10 4 6 0.73 +++
2. How could the odds for
Syracuse be 10:1 to win the NCAA playoffs based on their past
tournament record?
The odds of any team winning three
games are (1/2 * 1/2 * 1/2), or 1/8, if all teams were equal. However
in the case of Syracuse, they had to beat Loyola, probably Virginia,
and then eventually probably Princeton. Their power rating against
Princeton and Virginia would have made them underdogs (less than 1/2)
and their chances of beating Loyola were near 1/2 as both teams had
similar power ratings. Thus, their rating at the beginning of the
tourney was 1/10. Even Princeton with its undefeated season had at
best a 1/3 chance of winning the whole tournament. As the tourney
turned out, Syracuse beat Loyola by one goal, did not have to play
Virginia, but lost by one goal to underdog Maryland. The odds do not
take into account Syracuse's track record of making the final four
for their last 16 or so years nor does it take into account its
number of championships. The odds were based strictly on the power
ratings for the year 1997 and the tournament schedule.
3. Why is there a need for a power
rating? Aren't the other polls adequate?
The power rating is a poll based
strictly on scores and schedule. It is purely numerical and offers an
alternative, however good or bad, to the other polls. The rating
contains two components: the criteria and the numerical solver. The
criteria is a very subjective thing where one determines when a team
should be rewarded with points and when a team should lose points.
The numerical solver, on the other hand, computes the team's rating
based on the criteria, then recomputes over and over again, because
each team's rating is affected by the rating of each team it
plays.
When pollsters perform their rating,
they each have their own set of criteria in much the same fashion as
the power rating. However, the pollster is no match to the computer
when calculating the results. Therefore, the power rating can and
will employ a much more sophisticated set of criteria. Pollsters may
use different criteria which can under some circumstances make the
results look arbitrary. The power rating adheres to a strict set of
criteria and therefore results are not arbitrary. Next, polls are
subject to the criticism that they are not impartial and each
pollster may be driven by bias, intentional or unintentional. Whether
this exists or not, some fans will always be suspicious. The power
rating has no emotional investment or bias, since the computer merely
computes. If the criteria is biased, then the results would be, but
at least the criteria is stated up front. Thus the power rating can
be unbiased. The power rating is comprehensive in that it evaluates
all teams with no emphasis placed on just the good teams.
4. If coaching staffs are in
the best position to judge talent and team strength, why not leave
the rating to them?
Lacrosse coaches can only judge what
they see, and they do not see all of the teams. How can a team with
low visibility get its fair rating? Second, all coaches have
different criteria for rating teams and polls are based on a
collection of opinions which supposedly averages out to the fairest
assessment. The criteria for this average is then never clearly
understood and therefore impossible to challenge. Arising from this
inability to challenge is suspicion of unfairness or bias. At least
the power rating identifies its criteria and clearly substantiates
its findings. Finally, coaches can only do the top 15-20 teams before
it becomes an impossible task. Ask the pollsters who rate Division
III Men or Women to rate all 100 + teams and see how far they get.
The power rating is set up to evaluate all.
5. What credentials do you
bring to the table that makes you an expert on the
rankings?
Only my math and computer skills, but
that's all the power rating claims to use. The method applies to any
sport or competition, and thus knowledge of a particular sport is
irrelevant from a numerical standpoint.
6. How can a team be ranked
lower than other teams it beat?
As an example, Hartford beat Rutgers,
Harvard, and Towson State and yet Hartford ranks below them all. Here
is an example where the rating emphasizes goal difference more than
victory. The most difficult part of the algorithm was determining the
relative importance of victories and goal difference. Examining the
rating of the top twelve teams, Princeton is at 36 and Army at 24.8
-- a difference of 11 goals! Whereas the 13th to 26th teams have a
goal difference of only 2.48 goals. This means that teams ranked 13th
to 26th are so closely bunched that the slightest change in score or
home field advantage will effect their rating.
Hartford pr = 22.49 rank = 22
opponents ave pr = 18.99 rank = 33
date opponent power score goal difference gain or
rating actual expected loss
311 home vs Massachusetts 26.45 4 7 -3 -2.30 -
315 away at Rutgers 23.04 13 12 1 -2.21 ++
319 away at Harvard 22.67 10 9 1 -1.84 +
326 home vs New Hampshire 14.88 9 7 2 9.26 --
402 away at Delaware 19.04 11 8 3 1.79 +
405 away at Boston College 15.69 13 7 6 5.14
408 home vs Hofstra 24.55 2 7 -5 -0.40 --
412 home vs Fairfield 15.16 13 9 4 8.99 --
416 home vs Stony Brook 21.96 9 10 -1 2.19 -
419 away at Vermont 19.01 16 9 7 1.82 ++
419 away at VMI 11.60 16 9 7 9.22 -
423 away at Drexel 15.11 13 4 9 5.72 +
426 away at Providence 12.79 10 3 7 8.03
503 home vs Towson State 23.87 10 9 1 0.28
7. Do you have a job?
All of the the directors have
full-time positions elsewhere. All of the high school coordinators
probably also have full-time positions or are students. All
contributions to the site are on a voluntary basis and no
compensation is made.
8. Who sponsors this
rating?
We are not sponsored by any organization and have no affiliation with any group or league. We have formed an
affiliation with College Lacrosse USA for the purpose of sharing schedule,
score, and team information to better serve lacrosse fans.
9. Are you associated with
the NCAA or any school?
We have no association with the NCAA or with any of the organizations that
conduct lacrosse polls. Naturally, we do maintain contacts with numerous
coaches and sports information directors, and one of our directors is
associated with a Division III school, although not with its athletic
department
10. How do you find the time
to perform all this analysis?
The initial time invested in
developing the analysis program took weeks. Once done, the major task
becomes typing in the scores. Since we generally get
scores in a timely fashion, the remaining tasks are left to the
computer.
11. What are the Sagarin
ratings?
The Sagarin ratings are a numerical
rating system used for college football and basketball. They were
developed by Jeff Sagarin, a former MIT graduate student. The
LaxPower ratings were designed for lacrosse similar to these ratings.
12. How did LaxPower get off
the ground?
US Lacrosse felt that such a rating
would contribute positively to the sport of lacrosse and was designed
to be similar to the "Sagarin Ratings" for college football and
college basketball. Unlike the Sagarin ratings, women's divisions are
also included.
13. What is the Lacrosse
Championship Series?
It is a fictitious rating patterned
after the "Bowl Championship Series" based on a formula using polls,
computer rankings, strength of schedule and losses to determine the
best teams. It is our creation and has nothing to do with the
NCAA.
14. Does the strength of
schedules change throughout the season?
As the season progresses, the power
ratings for all teams will change and since the strength of schedule
is based on the average power ratings of all the teams its plays
within the same division, it too will change.
15. How important is goal
differential?
When the ratings of a team are
calculated, a win adds to the power rating of that team regardless of
the goal differential. The goal differential is taken into account
but its impact drops off with the larger difference. A 10 goal
victory has almost the same impact as a 20 goal difference.
16. How is the strength of
schedule computed?
The strength of schedule is currently calculated by taking the average of all of the opponents power ratings. We have developed
a relative power rating between different leagues and divisions and use these ratings, whenever possible to include all games for the
strength of schedule calculation.
17. Do the power ratings
include the results of the NCAA tournament?
For Men and Women Divisions I,II,III we currently do not include the scores of the NCAA tournaments because that would automatically
improve the strength of schedule of those teams by simply playing the best teams. Strength of Schedule is meant to indicate who
plays the toughest schedule during the season. Next year, we may allow the tournament results to influence the ratings but not the
strength of schedule.
| 
This is a sample of
the questions we're frequently asked through e-mail. If
you don't find the answer here or in the section about
how the power ratings are computed,
please don't hesitate to
send your questions
(laf@laxpower.com); we try to answer everything right away!
Also, don't forget that you can post questions and comments in the
LaxPower Forum;
it's a great place to interact
with fellow lacrosse fans and players.
