- Why rating?
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Wherever you go in the dancing community, one of the most discussed subjects is
always 'Who is better than whom'. However, there has never been an adequate way
to compare couples with each other. Existing ranking systems often do not agree
with popular perception, and are based on very simple rules. This leaves many
questions open to discussion. Who (in their time) was better, Paul Killick and
Hanna Kartunnen or Bryan Watson and Carmen? Paul and Hanna were first in the
ranking; however Bryan and Carmen were winning with them in the actual
competitions. Similarly, is Cocchi better than Kongsdale? You can see on our
forums the wide spectrum of opinions on the subject.
A very similar discussion applies to competitions, where people argue which
competition it is more worth it to go to. Many times, we have heard from
competitors that they are or are not going to a competition, because it is or
is not 'good'. It is the general opinion in dancing circles that the British
Open in Blackpool is *the* competition to go to. However, which is second? Is
the Russian Open better than the German Open? Is the International better than
the UK Open or not?
After some long deliberation, and many requests, we have decided to develop, and
soon release, a rating system which could be applied to, and hence allow to
compare, all dancing couples around the world.
- What is advantage of unified rating system?
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A world-wide rating system will allows us and possible other users, both now and
in the future, to provide measurable statistics in a wide spectrum. For
example:
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Being able to rate events, one could decide that reaching the semi-final in one
event maybe be better than winning another.
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We will be able to create a graph representing the change of a couple's
abilities over time. We will be able to provide a better comparison than the
existing one, of two or more couples, even if they did not take part in exactly
the same events.
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We can also go back in time, limited only by how back our data goes, and find
out any couple's rating for that day.
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By providing an event rating, we can stimulate competition organisers to
improve the quality of an event, and convince more dancers to take part in the
events.
- What is rating system?
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Our system is not supposed to replace any national or international ranking
system already existing, but rather to complement them. Our rating system is
based on the ELO chess rating system, used as a standard worldwide, and
suggested by some of the members on our forum. It has, however, been modified
(patent pending) to cater for both large and small competitions.
Take note also that this is a rating system, and not a ranking system. The
difference is that a rating system describes the current strength or quality of
a couple, rather than it's position in the chart.
In our opinion, it is nonsensical to compare, let's say an Amateur Ballroom
couple with a Professional Latin couple, hence there are seperate and different
rating tables for each style and group.
The basic principle is that we assume that a couple's rating increases as it
wins with other couples, and decreases when it loses. However, it increases
more when it wins with a stronger couple, and less if it wins with a weaker
couple. The basics of the system are described here.
The rating system for couples allows us to construct a rating system for events
and competitions. However, there are several factors which have to be
considered when trying to calculate the rating for an event. In our formulae,
we try to take into account most major factors which affect a dancer's
perception of the quality of an event or competition.
We rate any competition both as a whole, and by considering all the events of
different styles and groups (e.g. Amateur Latin is separate from both
Professional Latin and from Amateur Ballroom). When considering different
events, we do not differentiate between Rising Star events from Open events, if
they have the same group and style.
A more in-depth description of this system can be found here.
As much as we have tried to make this a reflection of quality of both dancers
and competitions, we are aware that it is not possible to define all factors of
dancing as a mathematical formula, and therefore this rating system might not
represent some peoples' perception of quality. In the same vein, this rating
system does not represent the subjective opinions of the Dancesport Info team.
- How can dancing community help?
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We are looking for people to cooperate with us to further improve our rating
system. We need beta testers to look at the results of the rating, to point out
possible mistakes, and to inform us of their subjective opinions, which may
lead to a better formula for rating. At the same time, we are looking for
mathematicians, who could the mathematical side of the rating system. Finally,
our system depends on a large database of accurate results, and will improve as
we get more data. Hence as always we are looking for contributions from the
whole of the dancing society and cooperation from competition organisers and
scrutineers.
If you wish to take part in the testing and improvement of this beta release,
please e-mail us for further details.
- Couple rating
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A competition is considered as a sequence of individual 'duels' between each
possible pairing of two couples. Let us consider the following example:
We have three couples - A, B and C - competing in an event. Couple A enter the
competition with a rating of 2000, couple B enter with a rating of 1500, and
Couple C with 1700. In the final, A was first, B was second and C third. Couple
A will then gain in rating because it won with B and C. Couple B will gain
points for winning with C, but lose points for losing with A, and Couple C will
lose points for losing to couples A and B. However, B will gain more points
from winning with C, than lose from losing to A, because B's original rating
was lower than C's. Conversely, C will lose more points from losing to B than
to A, for the same reasons.
The amount of points gained or lost in each 'duel' is calculated according to
the ELO system.
The total gain or loss of points by a couple is based on the sum of all the
results of the individual duels, and normalised by the number of people
competing, to avoid too great an influence of a big event. Only couples whose
original rating is in the same range are compared against each other, as there
is no point in penalising a non-experienced couple for losing against the world
champions. In the first event they part in, their first rating will be the
average rating of the couples which ended up in the same round, and if this is
not possible to calculate (e.g. all the couples are new), the following initial
values are assigned to the couples:
- Деца: 600
- Юноши: 900
- Младежи: 1200
- Аматьори: 1500
- Сеньори: 1200
- Over-50: 900
- Професионалисти: 1800
- Event and Competition rating
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An event is considered better if:
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Stronger couples (couples with a higher rating) compete in it
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There are more couples
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There are couples from more countries
To calculate the rating of events of a certain style and group (of which there
may be only one in a competition), we first create a list of all competitors
from these events. We sum their ratings, and normalise them by the number of
competitors. Then, this is increased proportionally to the number of countries
taking part. The final rating is then normalised to avoid too great a
difference between event ratings, and multiplied by a constant to make it more
readable.
To calculate the rating of a competition, we use a similar formula; however we
take into consideration all the dancers who took part in this particular
competition.
Please be aware that this ranking for events does not reflect does not include
any subjective factors, such as traditions, the venue or even the quality of
the floor.