Showing posts with label combo. Show all posts
Showing posts with label combo. Show all posts

Thursday, July 6, 2023

Another look at what NTRP rating combinations works best in Mixed 18 & Over? More Interesting Tennis League Stats

I've been looking at how different combinations of levels do in the 55 & Over Adult and 18 & Over Mixed, and just took a deeper dive on 55 & Over, so the same deeper dive on Mixed is in order.

The general observation has been that unbalanced pairs, e.g. a 4.5 and 3.5 in an 8.0 flight, tend to win more often than not, and this deeper dive will take a look at if this is actually expected or not based on the current ratings of the players.

The deeper dive on 55 & Over revealed that while the unbalanced pairs do win more often, they are always expected to, and often fall short of the expected winning percentage.  This may indicate a selection bias of sorts, where it is possible that only stronger players at their level opt to play as an unbalanced pair, thus skewing the stats in their favor, and there is not some inherent advantage to unbalanced pairs.

So on to taking a closer look at Mixed.  Specifically, I narrowed the matches analyzed to only those where I had an established rating for all 4 players and then looked at not just how often unbalanced pairs won, but how often they were expected to win.  The results were certainly interesting, and a bit different from what we saw for 55 & Over.

Note, the actual winning percentages are slightly different from the earlier post because some matches where the players didn't all have ratings have been filtered out.

For each level/gender below, I'm using 2022 18 & Over Mixed league data again and showing the percentage of the time the unbalanced pair won, followed by the percentage of the time the unbalanced pair had the higher combined ratings.  When the actual is higher than the expected, the unbalanced is overachieving, and when the actual is lower than the expected, they are underachieving.

The ratings used for this analysis are my Mixed Exclusive Estimated Dynamic NTRP Ratings I use for doing the various individual, team, and flight reports I offer.  The pairings are showing the male then female levels.

Starting with 6.0:

  • 3.5/2.5 vs 3.0/3.0 - 52.0% actual, 57.1% expected - underachieved
  • 3.5/2.5 vs 2.5/3.5 - 53.7% actual, 41.1% expected - overachieved big
  • 2.5/3.5 vs 3.0/3.0 - 48.0% actual, 59.3% expected - underachieved big

The 6.0 level can be tricky with a lot of new/unknown players at times, but we see the pairs with the higher rated male player win more often, and this is especially true when it is a 3.5 male vs a 2.5 male and the 3.5 male really overachieves vs expected.

But like I said, 6.0 is tricky, so on to 7.0 where players are a little less volatile:

  • 4.0/3.0 vs 3.5/3.5 - 58.7% actual, 56.4% expected - overachieved a bit
  • 4.0/3.0 vs 3.0/4.0 - 56.3% actual, 51.7% expected - overachieved
  • 3.0/4.0 vs 3.5/3.5 - 49.7% actual, 53.3% expected - underachieved

We again see the pair with the higher rated male wins more often, and we also see some over achievement for the 4.0/3.0 pairs.

Next, 8.0:

  • 4.5/3.5 vs 4.0/4.0 - 57.8% actual, 54.9% expected - overachieved
  • 4.5/3.5 vs 3.5/4.5 - 52.4% actual, 48.9% expected - overachieved
  • 3.5/4.5 vs 4.0/4.0 - 54.2% actual, 53.2% expected - overachieved a bit

The trend of unbalanced pairs overachieving continues by a decent 3-4% margin for the 4.5/3.5 pairs.

Next, 9.0:

  • 5.0/4.0 vs 4.5/4.5 - 61.6% actual, 53.6% expected - overachieved big
  • 5.0/4.0 vs 4.0/5.0 - 59.1% actual, 55.0% expected - overachieved
  • 4.0/5.0 vs 4.5/4.5 - 56.6% actual, 54.6% expected - overachieved a bit

The over achievement for unbalanced pairs is seen here too.

The counts for 10.0 are so low there is no point to doing the analysis here.

Given we see some to significant over achievement for the unbalanced pairs, especially at the higher levels, it may be that there is an inherent advantage in Mixed.  This is perhaps because at higher levels, players are able to employ strategies maximizing the difference in abilities taking advantage of having the stronger player.

It could also be that for the lower level player of unbalanced pairs, only the top players at that level self-select to play, and that gives an inherent ratings advantage over two "average" players on a balanced pair.

What do you think?

Wednesday, July 5, 2023

Another look at what NTRP rating combinations works best in Adult 55 & Over? More Interesting Tennis League Stats

A few days ago I took at look at what ratings combinations win the most in 55 & Over Adult league play.  What I found was consistent with earlier analysis I've done and that is that unbalanced pairs, e.g. a 4.0/3.0 pair in 7.0, beat balanced pairs, e.g. a 3.5/3.5, more than they lose.

What some pointed out, and I knew I wanted to do more research into, is that while the unbalanced pairs win more, that may be because of a selection bias of sorts, where it is possible that only stronger players at their level opt to play as an unbalanced pair, and the fact they win more often may be expected.  It is even possible that while they win more than lose, they may not win as often as expected.

For example, at 7.0, it may be that it is the strong 3.0s that are attracted to play or perhaps are recruited to play.  That means when they (say a 2.90 3.0) partner with an average 4.0 (3.75) vs two average 3.5s (3.25), the rating comparison is 6.65 vs 6.50, and the unbalanced pair has the higher combined ratings and thus is arguably expected to win.  Even if the 3.5s are a bit better (3.30) it is still 6.65 vs 6.60.

With that in mind, I went about digging deeper.  Specifically, I narrowed the matches analyzed to only those where I had an established rating for all 4 players and then looked at not just how often unbalanced pairs won, but how often they were expected to win.  The results were certainly interesting, if not a bit surprising.

Note, the actual winning percentages are slightly different from the earlier post because some matches where the players didn't all have ratings have been filtered out.

For each level/gender below, I'm using 2022 55 & Over Adult league data again and showing the percentage of the time the unbalanced pair won, followed by the percentage of the time the unbalanced pair had the higher combined ratings.  When the actual is higher than the expected, the unbalanced is overachieving, and when the actual is lower than the expected, they are underachieving.

The ratings used for this analysis are my Estimated Dynamic NTRP Ratings I use for doing the various individual, team, and flight reports I offer.

For the women:

  • 6.0 - 3.5/2.5 vs 3.0/3.0 - 48.7% actual, 54.7% expected - underachieved
  • 7.0 - 4.0/3.0 vs 3.5/3.5 - 54.6% actual, 54.5% expected - nearly perfectly as expected
  • 8.0 - 4.5/3.5 vs 4.0/4.0 - 56.2% actual, 62.3% expected - underachieved
  • 9.0 - 5.0/4.0 vs 4.5/4.5 - 66.9% actual, 73.7% expected - underachieved

Here we see the selection of matches change the actual percentages slightly, and at 6.0 the unbalanced actually lost slightly more than they won, but at three of the four levels, while the unbalanced won more, they were expected to win more than they did, so arguably underachieved.

For the men:

  • 6.0 - 3.5/2.5 vs 3.0/3.0 - 58.6% actual, 58.6% expected - exactly as expected
  • 7.0 - 4.0/3.0 vs 3.5/3.5 - 55.6% actual, 51.1% expected - overachieved
  • 8.0 - 4.5/3.5 vs 4.0/4.0 - 55.4% actual, 56.3% expected - slightly underachieved
  • 9.0 - 5.0/4.0 vs 4.5/4.5 - 50.9% actual, 55.2% expected - underachieved

Here the actual percentages vary a bit more with the selected matches, especially at 9.0.  And we also see that at 6.0 it is exactly as expected, the unbalanced overachieve at 7.0, but 8.0 has a slight underachieve and 9.0 a significant underachieve.

So, it may not be quite as clear cut as the earlier analysis showed.  While unbalanced pairs do win more than they lose, it appears it is because it is the right unbalanced pairs are playing and they are expected to win because they are higher rated overall, not just because they are an unbalanced pair.  And they may not even win as often as expected.

What do you think?  Is this more in-line with your experience than the initial analysis was?

Monday, July 3, 2023

What NTRP rating combinations works best in Mixed? More Interesting Tennis League Stats

I wrote yesterday about what ratings combinations work best for 55 & Over Adult play, today, I thought I'd start a refresh of the ratings combination analysis for Mixed I did around 8 years ago.

To start, I'll look at 18 & Over Mixed.  For reference, here is the post I did 8 years ago for the same division.

This time I will include 6.0 and 10.0 levels I omitted last time.  For each pairing I list, the first number will be the male level and the second the female level.

Starting with 6.0:

  • 3.5/2.5 pairs beat 3.0/3.0 pairs 52.7% of the time
  • 2.5/3.5 pairs beat 3.0/3.0 pairs 49.6% of the time
  • 3.5/2.5 pairs beat 2.5/3.5 pairs 56.2% of the time

Here, a slight to significant advantage to unbalanced when the male is the higher rated player.  The 2.5/3.5 is ever so slightly below 50%.

Next up, 7.0:

  • 4.0/3.0 pairs beat 3.5/3.5 pairs 58.3% of the time
  • 3.0/4.0 pairs beat 3.5/3.5 pairs 50.8% of the time
  • 4.0/3.0 pairs beat 3.0/4.0 pairs 55.1% of the time

This is similar to before (60%, 52%, 57%) so that form continues to hold.  Unbalanced with the higher rated male has the advantage, but unbalanced with the higher rated female has a slight advantage too.

Next up, 8.0:

  • 4.5/3.5 pairs beat 4.0/4.0 pairs 57.6% of the time
  • 3.5/4.5 pairs beat 4.0/4.0 pairs 53.5% of the time
  • 4.5/3.5 pairs beat 3.5/4.5 pairs 51.7% of the time

This is a bit different from last time (61%, 51%, 60%) with the unbalanced 3.5/4.5 pairs doing better than before.  Still, unbalanced has the advantage over balanced and unbalanced with the higher rated male stronger overall.

And 9.0:

  • 5.0/4.0 pairs beat 4.5/4.5 pairs 59.6% of the time
  • 4.0/5.0 pairs beat 4.5/4.5 pairs 56.1% of the time
  • 5.0/4.0 pairs beat 4.0/5.0 pairs 58.5% of the time
This compares with 57%, 58%, 51% last time, so a bit different, but the trend holds.  Unbalanced with more frequently, and the unbalanced with the higher rated male do so over the higher rated female.

Last, 10.0:

  • 5.5/4.5 pairs beat 5.0/5.0 pairs 27.0% of the time
  • 4.5/5.5 pairs beat 5.0/5.0 pairs 62.9% of the time
  • 5.5/4.5 pairs beat 4.5/5.5 pairs 66.7% of the time

Note there is so little play at this level that some of the totals for these match-ups are in the single digits so make of that what you will.

Aside from a couple anomalies at the 6.0 and 10.0 levels, the trend continues.  Unbalanced pairs win more often in Mixed.  The advantage is not huge, most of these winning percentages are between 50% and 60%, but it is consistent.

What do you think?  Is this consistent with what you see locally?

Sunday, July 2, 2023

What NTRP rating combinations works best in Adult 55 & Over? More Interesting Tennis League Stats

A popular discussion topic for USTA League teams that use combo-levels is what the best pairings are.  I've looked at this a number of years ago for Mixed, but thought it would be interesting to take a look at Adult 55 & Over.

The candidate leagues in this case are the 55 & Over Adult leagues with 6.0, 7.0, 8.0, and 9.0 flights where players up to a full two levels apart can play together.  For example, in 8.0 the playing combinations can be 3.5/4.5, 4.0/4.0, and 4.5/3.5.  The fundamental question is, when different pairings face each other, which wins more often?

Note for this analysis I'm only considering "at-level" pairings and not those where say a 3.5 and 4.0 play together as a "7.5" pair in an 8.0 flight.

I've done this before for Mixed, both 18 & Over and 40 & Over and in nearly every case, unbalanced pairs win more often than balanced pairs, generally between 52% and 60% depending on the exact scenario.  Mixed also has different genders to add to the permutations but the strongest tends to be unbalanced with the male the higher level player where that pair wins around 60% of the time.

What I did was to take a look at Adult 55 & Over matches from 2022 and broke it out by both gender and level.

For the women:

  • 6.0 - 3.5/2.5 pairs beat 3.0/3.0 pairs 51% of the time
  • 7.0 - 4.0/3.0 pairs beat 3.5/3.5 pairs 55% of the time
  • 8.0 - 4.5/3.5 pairs beat 4.0/4.0 pairs 57% of the time
  • 9.0 - 5.0/4.0 pairs beat 4.5/4.5 pairs 66% of the time

We see unbalanced pairs have the advantage, very slight at 6.0 but growing as the level goes up.

For the men:

  • 6.0 - 3.5/2.5 pairs beat 3.0/3.0 pairs 57% of the time
  • 7.0 - 4.0/3.0 pairs beat 3.5/3.5 pairs 56% of the time
  • 8.0 - 4.5/3.5 pairs beat 4.0/4.0 pairs 56% of the time
  • 9.0 - 5.0/4.0 pairs beat 4.5/4.5 pairs 57% of the time

The men are very consistent at 56-57% of the time the unbalanced pair wins.

This is pretty consistent with the Mixed results, unbalanced pairs win more often.  They theory is that the unbalanced pairs generally have the strongest player and if they employ a strategy to minimize the lower rated partner's weaknesses, the stronger player rises to the top.  At 55-57% for most scenarios it is obviously not a given that unbalanced pairs will win, but the trend is pretty clear.

What do you think?  Is this consistent with what you see in your leagues?


Update: I did a subsequent deeper dive looking at actual vs expected results here.