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Randomitsuki

Career predictons Hatsu 2010

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As you know, I even collected data about the highest KK ranks during rikishi careers. But by and large, SPSS has shown me that for rikishi in their third year onward the best predictor for "career highest rank" (to use the terms from the Doitsubase) is "highest rank" and not "highest KK rank".

I have little doubt that it's true in the aggregate, I just have a nagging feeling about those 7-0 and 6-1 jumps (especially the former) and the distortions they temporarily introduce in a particular rikishi's assessment. The prototypical case is probably Minaminoshima, who fluked a 7-0 and proceeded to follow up with six MK that dropped him back down beyond his yusho rank. My impression is that rikishi who go 7-0 and aren't clearly below their current talent level at the time tend to have a rather high likelihood of such big corrections, before they're back on their "actual career path" again.

Still, there's probably a healthy dose of hindsight involved, which is why I'm posting my reservations about Kaisei (his 3-1 start last basho almost caused me to waver...) and Takanoiwa, so they can be suitably ridiculed in a few months. (Shaking head...) I'm still pondering how I feel about Kurosawa...

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If you're up to it, I'd love to see a past snapshot (quite a ways back, say, from Hatsu 2000) so we can see what the biggest hits and misses have turned out to be. The algorithm may still struggle with the makushita level, but perhaps that just means there are more factors yet to be identified, and the combined brainpower of the forum might spot a few things.

Will Hatsu 2003 be OK as well? (I still have that file on my computer, the Hatsu 2000 was overwritten).

All those predictions are based on data until 2003, not on the current data.

First of all, the hits, i.e. guys correctly predicted for future sekitorihood ("high" is their best rank until 2003; "c-high" is their later or current career high):

Rank   Shikona		 high   c-high pred
==========================================
Ms1w   Dewanofuji	  ms1	J9	 M15 
Ms3e   Kakizoe		 ms3	K	  J5  
Ms3w   Hidenokuni	  ms3	J13	J9  
Ms6w   Kokkai		  ms1	K	  M7  
Ms9w   Tanaka		  ms1	J4	 J5  
Ms13w  Tochifudo	   ms3	J12	J12 
Ms14w  Yoshiazuma	  ms5	J14	M9  
Ms20e  Kotokikutsugi   ms20   S	  O   
Ms20w  Raido		   ms5	J2	 M2  
Ms21w  Toyonokuni	  ms2	J13	J9  
Ms27e  Tamaasuka	   ms14   M9	 M2  
Ms33w  Ryuo			ms33   M8	 M4  
Ms34e  Oga			 ms9	J6	 J12 
Ms37e  Hochiyama	   ms28   M14	M9  
Ms40w  Hakuba		  ms40   M16	M2  
Ms44e  Chiyohakuho	 ms27   M6	 O   
Ms46e  Ama			 ms15   O	  M4  
Ms50e  Kirinowaka	  ms50   J4	 M2  
Ms53e  Musashiryu	  ms53   M2	 M7  
Sd3w   Suzukawa		ms48   M9	 M2  
Sd6w   Toyonoshima	 sd5	S	  O   
Sd16e  Hakuho		  sd16   Y	  M2  
Sd25w  Hokutokuni	  sd25   J12	M2  
Sd28e  Koryu		   sd28   M11	M2  
Sd33w  Tokitenku	   sd33   K	  M13 
Sd43w  Yakigaya		ms55   M16	M11 
Sd49w  Hagiwara		sd49   S	  O   
Sd53e  Daiyuchi		sd53   J10	M9  
Sd62e  Hoshihikari	 sd46   J1	 J3  
Sd64w  Hakurozan	   sd64   M2	 O   
Sd65e  Mokonami		sd41   M7	 J5  
Sd76w  Kakuryu		 sd40   S	  M2

Then we have the misses - rikishi that made it to sekitori without my computer realizing it:

Rank   Shikona		 high   c-high pred
==========================================
Ms8w   Asofuji		 ms4	M13	D   
Ms19w  Yotsuguruma	 ms19   J8	 Ms9 
Ms21e  Shigezakura	 ms20   J12	Ms9 
Ms24e  Kyokunankai	 ms20   J2	 Ms17
Ms28e  Daimanazuru	 ms2	M16	D   
Ms32e  Dewanosato	  ms14   J14	D   
Ms33e  Maikaze		 ms8	J10	D   
Ms36e  Raiko		   ms20   J11	Ms9 
Ms39e  Kotokuni		ms16   J4	 Ms9 
Ms41e  Kotokasuga	  ms22   M16	Ms17
Ms49w  Roho			ms49   K	  Ms9 
Ms55w  Bushuyama	   ms23   M3	 Ms3 
Sd6e   Kotoshiiba	  ms50   J14	Ms29
Sd19e  Katayama		sd19   M13	Ms19
Jk30w  Kotooshu		jk30   O	  Ms34
Jk31w  Hoshikaze	   jk31   J12	Jd19

And finally - false alarms (rikishi for whom I predicted sekitorihood, but who haven't made it):

Rank   Shikona		 high   c-high pred
==========================================
Ms2w   Asamiyoshi	  ms2	ms2	O   
Ms5w   Shishio		 ms1	ms1	J12 
Ms9e   Fujinohana	  ms1	ms1	M15 
Ms17w  Nadatsukasa	 ms6	ms4	J9  
Ms19e  Kimenryu		ms4	ms4	J11 
Ms22e  Daishoma		ms7	ms4	M13 
Ms22w  Kakuo		   ms8	ms8	J12 
Ms23e  Tashiro		 ms7	ms7	M15 
Ms24w  Hokutoarashi	ms6	ms6	J7  
Ms25e  Asahibenten	 ms5	ms2	J9  
Ms26w  Otoryu		  ms3	ms3	J9  
Ms31w  Kirinofuji	  ms21   ms12   J1  
Ms36w  Murata		  ms36   ms3	M15 
Ms38e  Kotohino		ms9	ms9	J12 
Ms40e  Matsumidori	 ms30   ms14   J9  
Ms46w  Kirinoumi	   ms12   ms10   J9  
Ms48e  Kainowaka	   ms14   ms14   J9  
Ms52w  Hisanohana	  ms45   ms45   J1  
Ms57e  Musashifuji	 ms7	ms7	J12 
Sd5w   Tatsuyutaka	 sd5	ms12   J11 
Sd8e   Aoba			ms12   ms9	J1  
Sd10w  Ominami		 ms31   ms31   J9  
Sd12e  Takamihana	  ms4	ms4	J1  
Sd18e  Niioka		  sd18   ms41   M2  
Sd21e  Rachimi		 ms4	ms4	M9  
Sd23w  Hoshizakura	 ms59   ms12   M9  
Sd29e  Fusanohana	  ms13   ms13   J12 
Sd32w  Hananosato	  sd9	ms8	J9  
Sd39w  Daishochi	   sd23   ms15   M9  
Sd44e  Nakabuchi	   ms12   ms12   J12 
Sd49e  Kamakura		sd24   ms56   J3  
Sd61e  Yoshimura	   sd61   sd40   O   
Sd61w  Chojimaru	   sd46   ms3	J3  
Sd87e  Munakata		ms13   ms10   J12 
Sd93e  Satoyama		sd93   ms58   J1  
Sd97w  Nakanokuni	  sd97   ms3	O   
Sd99w  Ota			 sd99   sd66   M15 
Jd3w   Daionami		sd74   ms33   J5  
Jd25e  Wakamusashi	 jd25   sd53   O   
Jd30w  Nionoumi		jd30   ms16   O   
Jd37w  Shimada		 jd37   ms20   O   
Jd40w  Hokkairyu	   jd40   sd13   O   
Jd52w  Sasaki		  jd31   ms18   O

Edited by Randomitsuki

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Then we have the misses - rikishi that made it to sekitori without my computer realizing it:

Rank   Shikona		 high   c-high pred
==========================================
Ms39e  Kotokuni		ms16   J4	 Ms9 
Ms41e  Kotokasuga	  ms22   M16	Ms17
Sd6e   Kotoshiiba	  ms50   J14	Ms29
Jk30w  Kotooshu		jk30   O	  Ms34

I think we've identified one factor. (Shaking head...) Seriously though, many thanks for posting that, something to delve into the next few days...

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And perhaps as a warning (to myself as well) to not take these snapshots too seriously...

Rendaiyama, 22 years, 24 basho, Ms46->Ms17

Tochihiryu, 22 years, 24 basho, Ms43->J3

(Just to make sure - for that career length, the predictor being used is the high rank, not the current rank, right?)

Thanks for pulling out a specific example for me to try and latch on to my understanding gap.

SO assuming I understand what Asasho is assuming, Rendaiyama and Tochihiryu are in different subgroups of their cohort right? And thus bigly bigly different predictors.

But even if this is so, and creates much-needed deviation, what is the true range of a predictor window?

For example, in your first set you showed us 0 - 11 averaging 5.5 and 5.5 happens to be what? M15? And if 0 is Yokozuna then what is 11? So if a subgroup carries a potential range of Yokozuna to somewhere in high Makushita (?Ms3!) we are just going to call all of them M15? After all of your efforts to this point it seems rather pointless.

There must be a better way of creating more deviation and spreading out the predictor within the subgroup rather than using the midpoint and sticking it to every single member of the cohort. Asashosakari's oft-repeated comment on highest KK seems very apt. Of course you'd have to write new algorithms to test the idea and figure out how to apply it, but essentially a subclass system would be identified within each subgroup. This would result in another and much larger set of "no data results" so you'd have to create a secondary predictor column, let's call it "refined." If enough data exists, you could pinpoint the predictor rather using the midpoint.

Just in case I haven't made sense, let's take Kaisei and say within his cohort he is subgrouped with Tochinowaka (Ri).

For the sake of this argument, both have career highs of Ms6 and both are predicted for M3.

I am assuming that M3 represents a range of Y - M10. (0-4.25?)

So additional mining might find that subclasses exist within the subgroup:

those with career high KK within 3 points of the high, 5 points of the high, 8 points, and more than 8. [A B C D]

Kaisei is thus a 'D' and Tochinowaka having achieved KK from Ms 13 (7 ranks = 2 points) is an 'A' class within the subgroup.

Kaisei's prediction is refined to a range of M6 - M10 and so he is predicted at M8.

Tochinowaka is refined to Y-S and so Ozeki is the refined predictor for subclass A.

Also, can we have an asterisk somewhere for every member of a subgroup with say, less than 10 members? Of course not for this set, but if it's not too much trouble for the next one you do? And 10 was arbitrary. More stato-minded folks could debate on where they would want to see an asterisk. Essentially since we know when there is not enough data I'd like to know when we had "just barely enough data" as well.

Anyway, my critique notwithstanding, I am very impressed by the results of your first public run for the data.

Arigato gozaimashita.

ps - and of course you mentioned that your data shows the best results in Sandanme and below. Maybe that's what I am getting at. Some (intelligent) variation on my example above might provide what's missing to make the data more valuable above the sandame level. Also, why not publish a predictor history of key rikishi throughout their career. For example, all of Goeido's prediction values from Jonokuchi to Sandanme would help a lot in assessing our moving target.

Edit: aha! so while writing this post several of the issues were addressed by the main parties of this conversation. go figure (Shaking head...)

Edited by kaiguma

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SO assuming I understand what Asasho is assuming, Rendaiyama and Tochihiryu are in different subgroups of their cohort right? And thus bigly bigly different predictors.

Exactly.

But even if this is so, and creates much-needed deviation, what is the true range of a predictor window?

This depends on the cohort, the ranges will become narrower, the more data points I have.

For example, in your first set you showed us 0 - 11 averaging 5.5 and 5.5 happens to be what? M15? And if 0 is Yokozuna then what is 11? So if a subgroup carries a potential range of Yokozuna to somewhere in high Makushita (?!) we are just going to call all of them M15? After all of your efforts to this point it seems rather pointless.

You should not forget that this example was for rikishi in their third basho. Even the best rikishi of that cohort (Kitanoumi) was Jd95 at that time. Seen from this angle, having a window "somewhere between Yokozuna and high Makushita" isn't all too shabby for a guy in his third basho, and in some murky Jonidan areas - particularly as the cohort wasn't that big.

There must be a better way of creating more deviation and spreading out the predictor within the subgroup rather than using the midpoint and sticking it to every single member of the cohort.

That's what I suggested in post #24. I will think about spreading predictions within categories.

Also, can we have an asterisk somewhere for every member of a subgroup with say, less than 10 members? Of course not for this set, but if it's not to much trouble for the next one you do? And 10 was arbitrary. More stato-minded folks could debate on where they would want to see an asterisk. Eseentially since we know when there is not enough data I'd like to know when we had "just barely enough data" as well.

Sounds reasonable, and it will be implemented at some point. I don't know when this will be the case. The program that seeks for sub-groups within cohorts takes some 15 hours to run on a decent computer...

Anyway, my critique notwithstanding, I am very impressed by the results of your first public run for the data.

Thanks for the feedback - it is much appreciated. (Shaking head...)

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I wonder if the tradeoff between reduced fit and improved sample size would make it worth to combine cohorts a bit more. That Rendaiyama/Tochihiryu example came out rather extreme...given the limited level of detail in the age parameter (i.e. both 22 years, not 22y 0m and 22y 8m), perhaps stretching the basho groupings a bit (e.g. from 22 to 26 career basho in their case) would be beneficial once you're at double-digit counts?

Edit: Of course, that would result in the same number of cohorts but more population in each, so 15 hours probably won't get it done then...

Edited by Asashosakari

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I wonder if the tradeoff between reduced fit and improved sample size would make it worth to combine cohorts a bit more. That Rendaiyama/Tochihiryu example came out rather extreme...given the limited level of detail in the age parameter (i.e. both 22 years, not 22y 0m and 22y 8m), perhaps stretching the basho groupings a bit (e.g. from 22 to 26 career basho in their case) would be beneficial once you're at double-digit counts?

Edit: Of course, that would result in the same number of cohorts but more population in each, so 15 hours probably won't get it done then...

The idea is a good one (apart from the computational issue), but I think that many shortcomings might be already solved by implementing "floating" predictions rather than "categorical" predictions. I have just manually re-computed the Tochihiryu vs. Rendaiyama case, and instead of Juryo 3 vs. Makushita 17 it now has become Juryo 8 vs. Makushita 4. It still seems like a large gap given their career-highs of Ms43 vs. Ms46, but in fact the Ms43 were achieved on a larger banzuke than the Ms46. The converted ranks are 20 vs. 22, respectively.

It seems as if the implementation of floating predictions does not require much, so I'll definitely give it a try in the next days. Unfortunately, the week at work will be worrisome, and I've heard also that there is a basho going on.

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Don't worry about work, just call in sick! (Holiday feeling...)

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The idea is a good one (apart from the computational issue), but I think that many shortcomings might be already solved by implementing "floating" predictions rather than "categorical" predictions.

That will only solve the issue of large divergences within a cohort though, not the issue of wildly shifting projections between similar cohorts, right? What I mean is, (barring a new high rank) once the next basho rolls around Tochihiryu and Rendaiyama should still be projected relatively close to J8 and Ms4 as they're merely "one basho older", but it doesn't sound like that's necessarily going to be the case. That's where having a rolling window of aggregated cohorts would probably help, e.g. this time they'd be projected according to those historical rikishi with 22-26 basho, next time according to those with 23-27, etc.

Edited by Asashosakari

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Awwww.. Moriurara is already in decline... I had high hopes now that he knows what KK is like..

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The idea is a good one (apart from the computational issue), but I think that many shortcomings might be already solved by implementing "floating" predictions rather than "categorical" predictions.

That will only solve the issue of large divergences within a cohort though, not the issue of wildly shifting projections between similar cohorts, right? What I mean is, (barring a new high rank) once the next basho rolls around Tochihiryu and Rendaiyama should still be projected relatively close to J8 and Ms4 as they're merely "one basho older", but it doesn't sound like that's necessarily going to be the case. That's where having a rolling window of aggregated cohorts would probably help, e.g. this time they'd be projected according to those historical rikishi with 22-26 basho, next time according to those with 23-27, etc.

I played a little bit around with your idea. In most cases, there is no need to take several cohorts into account, as 5/6 of rikishi who were in your last cohort will follow you into your next cohort. However, there is one crucial stage, and that is when a rikishi gets older. In the first basho after a birthday, he'll suddenly find himself in a cohort that only has 1/6 overlap with the last one. In these cases your suggestion will have the best effects. One would get an even better inter-basho overlap by not only spreading out over basho number, but by spreading out over individual trajectories. For example, if a 16-year old rikishi is in his 7th basho, and next basho he will be 17 in his 8th basho, then it is better to spread over the cohorts (16-6, 16-7, 17,8) than over the cohorts (16-6, 16-7, 16-8). Programming for this will be a little tricky, but far from impossible. The computational overhead is also no problem, as the 15-hour runtime refers to getting the parameters, not to actually making predictions based on the parameters.

Alas, there is a rub to all this. If you spread over multiple cohorts, it will ultimately end up in more conservative predictions. At middle or late career stages this effect is negligible, but very early on this could become an issue. For instance, if I decided to spread cohorts for someone in his 3rd basho (i.e. include guys in their 2nd, their 3rd, and their 4th basho) and take the total average of these three cohorts, this average would be higher (and the predicted rank would be lower) than the average for 3rd basho only - this is a side effect of faster promotions in the early career stages.

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Thanks for the really interesting analysis! I have one suggestion, if I could be so bold. It seems that because the preferred indicator changes from basho to basho, you end up with a lot of variability in the expected trajectory. So bearing that in mind, I would be interested to see a moving average of what the predicted trajectories have been over the past year.

I feel I haven't written that too clearly so here's a made-up example. Suppose over the course of a year Goeido's predicted career high changes as follows:

96 (Hatsu), 99 (Haru), 100 (Natsu), 99 (Nagoya), 97 (Aki), 99 (Kyushu)

Then the number I would be interested in seeing is (96 + 99 + 100 + 99 + 97 + 99)/6

which might give a more stable and perhaps more accurate prediction for higher-ranking rikishi.

Obviously with rikishi who have had short careers this might actually make matters worse because the earlier predictions will be based on less informative data.

Anyway thanks a lot, I'm impressed by your hit-rate below Makushita.

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I have one suggestion, if I could be so bold. It seems that because the preferred indicator changes from basho to basho, you end up with a lot of variability in the expected trajectory. So bearing that in mind, I would be interested to see a moving average of what the predicted trajectories have been over the past year.

Thanks for the input! ;-)

However, implementing this idea would require a complete rewrite of the code, as I do not save past predictions in a format that can be easily used. Moreover, while your suggestion certainly will stabilize the predictions, there can be such thing as too much stabilization. If a rikishi strongly improves, your method would be quite slow to react to this change.

Still, I might give it a try, but given the massive re-coding it's not my preferred strategy right now.

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Alas, there is a rub to all this. If you spread over multiple cohorts, it will ultimately end up in more conservative predictions. At middle or late career stages this effect is negligible, but very early on this could become an issue. For instance, if I decided to spread cohorts for someone in his 3rd basho (i.e. include guys in their 2nd, their 3rd, and their 4th basho) and take the total average of these three cohorts, this average would be higher (and the predicted rank would be lower) than the average for 3rd basho only - this is a side effect of faster promotions in the early career stages.

No, I was also thinking of a sort of escalating approach, where the very early career stages are estimated according to single basho, and then later perhaps three basho, and even later five etc. I agree that averaging things too much in the beginning is likely to obscure important data points. And besides, for the early stages there should also be more data anyway since almost every rikishi will see e.g. his third basho, so there's (I think...) less of a need to create a larger sample size by grouping.

Of course, I don't have to implement it, so anything I suggest here is little concerned with the practicality of it all. ;-)

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Shikona		 Rank   Age Exp Best Rank	 Prediction	
==========================================================
Takanoiwa	   Ms13w  19  7   Makushita 13  Ozeki

I'll boldly predict he'll be exhibit #239 for my belief that career-high rank is not quite useful when it deviates significantly from the career-high KK rank. (Kaisei will be exhibit #238.)

Still, there's probably a healthy dose of hindsight involved, which is why I'm posting my reservations about Kaisei (his 3-1 start last basho almost caused me to waver...) and Takanoiwa, so they can be suitably ridiculed in a few months. (Sign of approval...) I'm still pondering how I feel about Kurosawa...

Good thing nobody listens to me anyway.

(I still find Kaisei's sumo extremely unimpressive though...)

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I just wanted to admit that I haven't worked a bit on the career predictions data. (Sign of approval...)

As the data are still plagued with many flaws, I will not publish them until further notice.

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