Golf stats and correlation to average score vs. handicap

[natureboy]

I have a better approach to do a simpler tracking of average drive quality than the 'percent of hole' covered I suggested above. It's a simplified version of 'Effective Driving Distance' that I calculated for PGA players for the 2013 season.

I found some stats for a range of handicaps on a 'typical course' with tee shot parameters. I added the curve for the effective distance loss for being in the rough (distance gap where fairway proximity equals rough proximity). Also added recommended tee lengths and handicaps.

Basically you measure your drive distance from the tee (based on rangefinder, gps, your estimated approach distance, or a landmark on the course) and record if it's in the rough or fwy, penalty, or lost/OB.

You then come up with an average drive distance for all tee shots that find the fairway. You then recalculate an 'effective driving distance' assessing the rough penalty for your handicap (or average the rough penalty at your avg distance and your handicap if they don't match up). That's the rough-adjusted 'effective driving distance'. You do a similar 'effective distance' calculation for both rough and penalties wherein you add 2 shots to the denominator (possible fairways) for the lost stroke opportunities to put the ball in play at your average distance. If the drive is hit to point requiring a penalty drop or recovery shot, you estimate the portion of a full approach stroke you think the position cost you and add that number (plus one for the penalty stroke) to the denominator (possible fairways). Then you see how you match up against the 'typical course' benchmark values in the table below.

Fairway bunkers are more penal than rough, but unless your course has a very large number of them (or sandy waste areas) I think you can get away with just considering them 'rough' for the calculation, or maybe make them a fraction more penal (in effective lost distance) than the rough.

My course is fairly penal on most holes for a wide shot with deep woods and high brush, yet despite my low Fwy% & percent of L/OB off the tee, my drive distance is still the advantage I thought (relative to my HCP anyway) and my three-putting, flubbed short game / recovery shots were the pieces averaging above my HCP. If you are very consistent (fewer wild drives), but still hit a lot of rough then your Effective Distance ranges between rough-adjusted and rough & penalty-adjusted will be tighter indicating consistency as a strength relative to your HCP (unlike me ).

Try it out and let me know how the numbers track with your game stats and experience.

Avg Score	65	70	75	80	85	90	95	100	105	110	115
~ HCP (Course Rating 75)	-11.1	-6.5	-1.9	2.7	7.3	11.9	16.5	21.1	25.7	30.3	34.9
~ HCP (Course Rating 72)	-8.6	-4.0	0.6	5.2	9.8	14.4	19.0	23.6	28.2	32.8	37.4
~ HCP (Course Rating 68)	-4.0	0.6	5.2	9.8	14.4	19.0	23.6	28.2	32.8	37.4	42.0
~ USGA Reccd Tees (Yards) Per Driver Dist	7,542	7,016	6,573	6,232	5,986	5,814	5,687	5,568	5,419	5,200	4,861
Broadie-Ko 'Typical Course' Simulation
Degrees Offline From Tee	2.7	3.8	4.7	5.5	6.2	6.9	7.4	7.9	8.4	9.0	9.5
# Fairways	10.8	9.1	8.0	7.2	6.7	6.4	6.3	6.3	6.3	6.2	6.0
% Fairway	77.0	65.3	56.9	51.2	47.6	45.7	45.0	44.9	44.9	44.5	43.2
75% Driving Distance (Good Drives)	314.1	283.1	260.3	244.3	233.3	225.9	220.6	215.7	209.7	201.1	188.3
Avg Driving Distance	298.8	266.7	242.5	224.6	211.6	202.0	194.5	187.6	179.7	169.5	155.5
Effective Drive Distance (Rgh Adj)	286.0	254.3	232.2	216.7	205.7	197.7	191.3	185.2	178.0	168.2	154.5
Effective Drive Distance (Rgh & Penalty Adj)	281.2	248.5	225.3	208.3	195.6	185.6	176.9	168.3	158.5	146.4	131.1
# Long Tee Shot To Penalty	0.12	0.16	0.22	0.28	0.36	0.46	0.57	0.70	0.86	1.04	1.25
% Long Tee Shot To Penalty	0.86	1.17	1.55	2.02	2.59	3.27	4.08	5.03	6.14	7.43	8.91
Effective Yardage Loss On Pxy From Rough	55.7	35.8	23.7	16.1	11.2	8.0	5.8	4.3	3.2	2.4	1.9

My stats:

	By Dist	By HCP
Fairway %	38.4	38.4
# Long Tee Shot To Penalty	1.53	1.53
% Long Tee Shot To Penalty	10.96	10.96
75% Driving Distance (good drive potential)	264.3	264.3
Avg Drive Dist	246.8	246.8
Effective Drive Distance (Rgh Adj)	228.5	243.9
Effective Drive Distance (Avg Rgh Adj)	236.2	236.2
Effective Drive Distance (Rgh & Penalty Adj)	187.4	200.1
Effective Drive Distance (Avg Rgh & Penalty Adj)	193.7	193.7
Effective Yardage Loss From Rough	29.7	4.62
Effective Yardage Loss From Rough (Avg)	17.2	17.2

[Lihu]

I have a better approach to do a simpler tracking of average drive quality than the 'percent of hole' covered I suggested above. It's a simplified version of 'Effective Driving Distance' that I calculated for PGA players for the 2013 season. … Try it out and let me know how the numbers track with your game stats and experience.

Not sure how to calculate the required entries. . . I'm not exactly sure what he scores have to do with the distances you play since it seems like you have handicap listed as well? How do you assess penalty from being in rough? What if you lose like 1 stroke every 10 holes just from being in first cut rough assuming you lost something like 50 yards or something like that?

[RandallT]

I have a better approach to do a simpler tracking of average drive quality than the 'percent of hole' covered I suggested above. It's a simplified version of 'Effective Driving Distance' that I calculated for PGA players for the 2013 season.

I found some stats for a range of handicaps on a 'typical course' with tee shot parameters. I added the curve for the effective distance loss for being in the rough (distance gap where fairway proximity equals rough proximity). Also added recommended tee lengths and handicaps.

Basically you measure your drive distance from the tee (based on rangefinder, gps, your estimated approach distance, or a landmark on the course) and record if it's in the rough or fwy, penalty, or lost/OB.

You then come up with an average drive distance for all tee shots that find the fairway. You then recalculate an 'effective driving distance' assessing the rough penalty for your handicap (or average the rough penalty at your avg distance and your handicap if they don't match up). That's the rough-adjusted 'effective driving distance'. You do a similar 'effective distance' calculation for both rough and penalties wherein you add 2 shots to the denominator (possible fairways) for the lost stroke opportunities to put the ball in play at your average distance. If the drive is hit to point requiring a penalty drop or recovery shot, you estimate the portion of a full approach stroke you think the position cost you and add that number (plus one for the penalty stroke) to the denominator (possible fairways). Then you see how you match up against the 'typical course' benchmark values in the table below.

Fairway bunkers are more penal than rough, but unless your course has a very large number of them (or sandy waste areas) I think you can get away with just considering them 'rough' for the calculation, or maybe make them a fraction more penal (in effective lost distance) than the rough.

My course is fairly penal on most holes for a wide shot with deep woods and high brush, yet despite my low Fwy% & percent of L/OB off the tee, my drive distance is still the advantage I thought (relative to my HCP anyway) and my three-putting, flubbed short game / recovery shots were the pieces averaging above my HCP. If you are very consistent (fewer wild drives), but still hit a lot of rough then your Effective Distance ranges between rough-adjusted and rough & penalty-adjusted will be tighter indicating consistency as a strength relative to your HCP (unlike me ).

Try it out and let me know how the numbers track with your game stats and experience.

As always, impressive analysis and food for thought, @natureboy ! I'll have to digest this a bit.

I've been leaning toward a simple strokes gained approach myself (and building a simplified spreadsheet bit by bit over time, with help of others). I like simplicity, and I'd have to dive deeper into the words above to see if I can glean the key ideas for simplicity. Can you take a crack at a one or two sentence overview to sell me on what exactly you are saying the benefits of this are. I think you are saying:

"With just a bit of extra effort on tracking the success of your drives, you can see a correlation between your overall score and your driving performance, regardless of what handicap level you are. The benefits of doing this are that you can see if you are driving well compared to what you should for your handicap, or if your driving is below a typical person at your handicap. "

Am I in the ballpark?

[Lihu]

Btw, just to be clear, I am also impressed by @natureboy nice work. . .

[natureboy]

As always, impressive analysis and food for thought, @natureboy ! I'll have to digest this a bit.

I've been leaning toward a simple strokes gained approach myself (and building a simplified spreadsheet bit by bit over time, with help of others). I like simplicity, and I'd have to dive deeper into the words above to see if I can glean the key ideas for simplicity. Can you take a crack at a one or two sentence overview to sell me on what exactly you are saying the benefits of this are. I think you are saying:

"With just a bit of extra effort on tracking the success of your drives, you can see a correlation between your overall score and your driving performance, regardless of what handicap level you are. The benefits of doing this are that you can see if you are driving well compared to what you should for your handicap, or if your driving is below a typical person at your handicap. "

Am I in the ballpark?

That sounds like a good summary, and certainly applies to SG too. I don't see my method as extra effort during the round relative to SG since you have to record distance and lie condition as well. On the course I have just been noting on my own scorecard a shot-by-shot condition so can just transfer the results to spreadsheet after. I will just start adding tee distances (harder for me on par 5's). I like to do it myself, but most people will probably find the game golf and gps apps like arccos or even "Shot-By-Shot" simpler and probably more effective. Like I said - this is the poor man's version.

When I collect round info, I'm going to do strokes gained side-by-side and see what the slope correlation is per round with the score for multiple rounds. I expect that SG will probably be stronger, but one of the reasons I haven't done it yet is that working the distance table into excel for for shot-by-shot calculation seems cumbersome. May be easy. Just haven't tried it yet. For my 'simple' tracking this year I plan to add an 'awful' notation to see where I am vs. Broadie's long & short game awful shot baselines.

My 'Effective Dirving Distance' approach fits well into the stat tracker I've already made. One of the benefits is that I see the range of where I am on the continuum of handicaps along with my other stats so strengths / weaknesses stand out when I shade in where my own averages lie. The Strokes Gained number is also pretty intuitive as a 'score' per shot type, but to see where I lie relative to my handicap I have to add the relative stroke difference to the average pro on the course I play. Not sure this would be 'correct' statistically as the baseline for different shot types depending on lie are shaped differently for different handicaps, such as with the lower 'effective distance' penalty for being in the rough for higher handicap players in my chart.

I don't think it's as strong as strokes gained on a mapped course with an amateur shot database, because elevations changes affect the expected drive distance for individual holes, but it should be pretty solid for multi-round averages - and you can see where about you are relative to your HCP if you only have a known average drive distance, a Fwy%, & a L/OB %.

On a purely personal level, I like that it shows me in a simple number directly comparable to my good drive distance how much my errant tee shots are costing me.

I'm not exactly sure what he scores have to do with the distances you play since it seems like you have handicap listed as well?

How do you assess penalty from being in rough? What if you lose like 1 stroke every 10 holes just from being in first cut rough assuming you lost something like 50 yards or something like that?

So you add up your total driving distance on hit fairways (or your known average * Fwy%). Add up your total driving distance on missed fairways (or your known avg dist * Rgh%). Multiply the 'effective distance loss' by the number of drives to rough and subtract that from the total distance of drives to rough. **I am not sure whether the accuracy penalty from rough is more related to skill/experience or distance (waiting to hear back from Dr. Broadie...may be a while given how busy he is lately) so I did two separate calculations based on the rough penalty corresponding to my average distance and for my current handicap and one more where I averaged the two rough penalties.** Then you have a final total driving distance for the round adjusted for your visits to the rough (both in distance from the tee and effect of the lie). Divide this total distance by driving opportunities (possible fairways) for the 'Effective Driving Distance' adjusted for rough for the round. Across 5-10 rounds you should have a decent picture.

For the tee penalty (L/OB) adjustment. I did the same calculation as above, but for every stroke & distance penalty I added two to the possible fairways denominator (lost opportunities to move the ball toward the cup). For tee shots hit to hazards or recovery situations you would assess how much of a full drive's distance it cost you and use a fraction between 0 and 1 plus the penalty stroke (if you take one). If I covered ~ 75% of my avg distance on the drive before it crossed a hazard boundary and I had to drop, I would add 1.25 to possible fairways. Not much water on my course so it was strictly stroke & distance for my wayward shots. This is the more accurate reflection of your full driving performance, but I thought it was interesting to have the 'rough only and 'rough plus penalty' to compare side-by-side since a higher rough adjusted distance with a small added penalty adjusted distance would reflect tighter driving / consistency.

I added the recommended tee lengths just as a possible self-assessment factor if you are playing a course too long or too short for you (too narrow in my case) it could reflect in the stats. The recommended tee lengths are based by the USGA on average driving distance which is correlated with HCP.

The rough 'penalty' is the effective loss in proximity on approach from being in a rough lie. Pros hit with the same proximity (in the average approach range - not on a driveable par 4) from ~ 50 yards back in the fairway relative to a lie in the rough. Less of an effective distance loss for amateurs per the drop-off on the chart. The penalty is a yardage cost to the driving distance on your accuracy & scoring chances. This is why I think this approach should correlate more strongly with average score than just fairway %.

[Lihu]

Quote:

OriginallyW Posted by Lihu

How do you assess penalty from being in rough? What if you lose like 1 stroke every 10 holes just from being in first cut rough assuming you lost something like 50 yards or something like that?

So you add up your total driving distance on hit fairways (or your known average * Fwy%). Add up your total driving distance on missed fairways (or your known avg dist * Rgh%). Multiply the 'effective distance loss' by the number of drives to rough and subtract that from the total distance of drives to rough. **I am not sure whether the accuracy penalty from rough is more related to skill/experience or distance (waiting to hear back from Dr. Broadie...may be a while given how busy he is lately) so I did two separate calculations based on the rough penalty corresponding to my average distance and for my current handicap and one more where I averaged the two rough penalties.** Then you have a final total driving distance for the round adjusted for your visits to the rough (both in distance from the tee and effect of the lie). Divide this total distance by driving opportunities (possible fairways) for the 'Effective Driving Distance' adjusted for rough for the round. Across 5-10 rounds you should have a decent picture.

The rough 'penalty' is the effective loss in proximity on approach from being in a rough lie. Pros hit with the same proximity (in the average approach range - not on a driveable par 4) from ~ 50 yards back in the fairway relative to a lie in the rough. Less of an effective distance loss for amateurs per the drop-off on the chart. The penalty is a yardage cost to the driving distance on your accuracy & scoring chances. This is why I think this approach should correlate more strongly with average score than just fairway %.

I added the recommended tee lengths just as a possible self-assessment factor if you are playing a course too long or too short for you (too narrow in my case) it could reflect in the stats. The recommended tee lengths are based by the USGA on average driving distance which is correlated with HCP.

I'm guessing that your swing type also has something to do with this, rather than just "skill". For instance, I had a shallower attack angle 4 months ago, and realized that my performance from rough was pretty bad. In order to make rough easier to get out of, I determined that a steeper swing helps. The only real consequence was that I put deeper divots into the fairways, and could suddenly hit a lot farther in general. At this point, first cut rough and fairways are about the same for me in terms of iron distances, so first cut doesn't cost me any measurable strokes but only fractions if averaged over 5 rounds.

I can see how you should play the recommended tee lengths, but the yardages are really short, for instance, you have a person shooting 85 playing from 6000 yards. Let's say a person shoots 85 on a 6300 yard course but now decides to play from 6000 yards their score would be a lot lower than 85. They might shoot closer to 80 which would then put them on the 6300 yard course. So, I'm not sure how to correlate the yardage and the score?

[RandallT]

That sounds like a good summary, and certainly applies to SG too. I don't see my method as extra effort during the round relative to SG since you have to record distance and lie condition as well. On the course I have just been noting on my own scorecard a shot-by-shot condition so can just transfer the results to spreadsheet after. I will just start adding tee distances (harder for me on par 5's). I like to do it myself, but most people will probably find the game golf and gps apps like arccos or even "Shot-By-Shot" simpler and probably more effective. Like I said - this is the poor man's version.

When I collect round info, I'm going to do strokes gained side-by-side and see what the slope correlation is per round with the score for multiple rounds. I expect that SG will probably be stronger, but one of the reasons I haven't done it yet is that working the distance table into excel for for shot-by-shot calculation seems cumbersome. May be easy. Just haven't tried it yet. For my 'simple' tracking this year I plan to add an 'awful' notation to see where I am vs. Broadie's long & short game awful shot baselines.

My 'Effective Dirving Distance' approach fits well into the stat tracker I've already made. One of the benefits is that I see the range of where I am on the continuum of handicaps along with my other stats so strengths / weaknesses stand out when I shade in where my own averages lie. The Strokes Gained number is also pretty intuitive as a 'score' per shot type, but to see where I lie relative to my handicap I have to add the relative stroke difference to the average pro on the course I play. Not sure this would be 'correct' statistically as the baseline for different shot types depending on lie are shaped differently for different handicaps, such as with the lower 'effective distance' penalty for being in the rough for higher handicap players in my chart.

I don't think it's as strong as strokes gained on a mapped course with an amateur shot database, because elevations changes affect the expected drive distance for individual holes, but it should be pretty solid for multi-round averages - and you can see where about you are relative to your HCP if you only have a known average drive distance, a Fwy%, & a L/OB %.

On a purely personal level, I like that it shows me in a simple number directly comparable to my good drive distance how much my errant tee shots are costing me.

Ok, gotcha, it's making more sense as I digest it all. And I'm not in any way skeptical of the "extra effort," as I'm typically someone here who thinks it's not burdensome to collect info yourself. Over time, it's getting harder and harder to argue against the power of Game Golf and Arccos, as they collect it all automatically, but not all of us can shell out that kind of money or really want to bother with extra technology during their rounds.  There may always be a market for paper scorecards and Excel spreadsheets for the "poor man's" version, as you say.

I can shoot you a sample spreadsheet for Strokes Gained if you PM me. I've got one that works in Apple Numbers, but very few people have that, I understand. It works on an iPad if you have one of those. When I export to Excel, it is hideously broken, and all the king's horses and all the king's men thus far haven't been able to resurrect a functioning version. But if you like, I could do that so you have the tables for strokes gained (every yardage and every lie has an assigned stroke value on a lookup table). Then you can do with it what you want.

I'll tinker with your ideas here to see if I can make something fit into my method of score analysis. Interesting stuff.

[Lihu]

[QUOTE name="natureboy" url="/t/80313/golf-stats-and-correlation-to-average-score-vs-handicap/54#post_1145124"] [CONTENTEMBED=/t/80313/golf-stats-and-correlation-to-average-score-vs-handicap/54#post_1144833 layout=inline] [/CONTENTEMBED] That sounds like a good summary, and certainly applies to SG too. I don't see my method as extra effort during the round relative to SG since you have to record distance and lie condition as well. On the course I have just been noting on my own scorecard a shot-by-shot condition so can just transfer the results to spreadsheet after. I will just start adding tee distances (harder for me on par 5's). I like to do it myself, but most people will probably find the game golf and gps apps like arccos or even "Shot-By-Shot" simpler and probably more effective. Like I said - this is the poor man's version. When I collect round info, I'm going to do strokes gained side-by-side and see what the slope correlation is per round with the score for multiple rounds. I expect that SG will probably be stronger, but one of the reasons I haven't done it yet is that working the distance table into excel for for shot-by-shot calculation seems cumbersome. May be easy. Just haven't tried it yet. For my 'simple' tracking this year I plan to add an 'awful' notation to see where I am vs. Broadie's long [/QUOTE] Ok, gotcha, it's making more sense as I digest it all. And I'm not in any way skeptical of the "extra effort," as I'm typically someone here who thinks it's not burdensome to collect info yourself. Over time, it's getting harder and harder to argue against the power of Game Golf and Arccos, as they collect it all automatically, but not all of us can shell out that kind of money or really want to bother with extra technology during their rounds.  There may always be a market for paper scorecards and Excel spreadsheets for the "poor man's" version, as you say.  I can shoot you a sample spreadsheet for Strokes Gained if you PM me. I've got one that works in Apple Numbers, but very few people have that, I understand. It works on an iPad if you have one of those. When I export to Excel, it is hideously broken, and all the king's horses and all the king's men thus far haven't been able to resurrect a functioning version. But if you like, I could do that so you have the tables for strokes gained (every yardage and every lie has an assigned stroke value on a lookup table). Then you can do with it what you want. I'll tinker with your ideas here to see if I can make something fit into my method of score analysis. Interesting stuff.

The main complaint with those electronic systems is that I'm not all that careful about putting my clubs back into the bag. I borrowed one unit from a friend and had to replace the tags that broke. It doesn't really keep track of distances very accurately either. Not sure about the Arcos, but I'm pretty sure I would break the transmitters within a week of use. . . I use a phone app, and my cart has a nice place to hold the phone. Unfortunately, not to take videos. That might be a part of golf cart 2.0. The main issue with the phone app is the gps accuracy as well. It's more accurate to remember where the ball lands and use Google earth.

[natureboy]

 

Ok, gotcha, it's making more sense as I digest it all. And I'm not in any way skeptical of the "extra effort," as I'm typically someone here who thinks it's not burdensome to collect info yourself. Over time, it's getting harder and harder to argue against the power of Game Golf and Arccos, as they collect it all automatically, but not all of us can shell out that kind of money or really want to bother with extra technology during their rounds.  There may always be a market for paper scorecards and Excel spreadsheets for the "poor man's" version, as you say. 

 

I can shoot you a sample spreadsheet for Strokes Gained if you PM me. I've got one that works in Apple Numbers, but very few people have that, I understand. It works on an iPad if you have one of those. When I export to Excel, it is hideously broken, and all the king's horses and all the king's men thus far haven't been able to resurrect a functioning version. But if you like, I could do that so you have the tables for strokes gained (every yardage and every lie has an assigned stroke value on a lookup table). Then you can do with it what you want.

 

I'll tinker with your ideas here to see if I can make something fit into my method of score analysis. Interesting stuff.

The main complaint with those electronic systems is that I'm not all that careful about putting my clubs back into the bag. I borrowed one unit from a friend and had to replace the tags that broke. It doesn't really keep track of distances very accurately either. Not sure about the Arcos, but I'm pretty sure I would break the transmitters within a week of use. . .

I use a phone app, and my cart has a nice place to hold the phone. Unfortunately, not to take videos. That might be a part of golf cart 2.0. The main issue with the phone app is the gps accuracy as well. It's more accurate to remember where the ball lands and use Google earth.

One thing I left out is if you do a simple calculation just based on a known average driving distance then you have to multiply the fairway and rough number by possible fairways (driving holes) as part of the calculation so it would be:

Rough Only: (PossFwy * Fwy% * AvgDist + PossFwy * Rgh% * (AvgDist - RghPnlty ) ) / PossFwy

RghPnlty: Use both the penalty at your average distance and your HCP for a range and/or an average of the two to get more of a mid-point value.

Rough & L/OB/Hz: (PossFwy * Fwy% * AvgDist + PossFwy * Rgh% * (AvgDist - RghPnlty) ) / (PossFwy + # PenaltyAdj )

PenaltyAdj: Add 2 for every L/OB. Also add 1 (for penalty) plus decimal fraction between 0 & 1 (for distance) for penalty drop depending on fraction of avg drive lost at hazard crossing point. May also consider adding recovery shots under the second procedure, but since a '% tee shots hit to recovery' stat by HCP is not included in the 'Efffective Driving Distance' baseline, this may reduce the average driving distance too much. Anyone have that data?

For collecting actual round data you would drop the PossFwy & Fwy% and just tally the measured distances of drives to Fwy & Rgh.

[natureboy]

Re. recovery shot option: in adding to possibly fairways, no penalty shot is included so it's only a fraction of a stroke. But it would be the estimate of how much of your next shot the recovery position cost you so of you could only hit 75% of the approach distance you could hit from that same distance on the fairway it would be a .25 fraction added to possible fairways.

I found some data on recovery shots by HCP (high handicappers), but not sure what to use as the average percent of lost approach shot distance would be appropriate. Any thoughts? I suppose that it would be somewhere around 66% of average approach distance for a .34 fraction added to possible fairways for the baseline average. Likely lower HCP's are more skilled at hitting a higher fraction of the normal approach from the fairway on recovery lies. Also, shots hit to recovery are probably shorter on average due to interference on carry / roll. I would estimate the average distance of tee shots hit to recovery around 80%-90% of the average drive distance.

Thoughts?

[Lihu]

Re. recovery shot option: in adding to possibly fairways, no penalty shot is included so it's only a fraction of a stroke. But it would be the estimate of how much of your next shot the recovery position cost you so of you could only hit 75% of the approach distance you could hit from that same distance on the fairway it would be a .25 fraction added to possible fairways.

I found some data on recovery shots by HCP (high handicappers), but not sure what to use as the average percent of lost approach shot distance would be appropriate. Any thoughts? I suppose that it would be somewhere around 66% of average approach distance for a .34 fraction added to possible fairways for the baseline average. Likely lower HCP's are more skilled at hitting a higher fraction of the normal approach from the fairway on recovery lies. Also, shots hit to recovery are probably shorter on average due to interference on carry / roll. I would estimate the average distance of tee shots hit to recovery around 80%-90% of the average drive distance.

Thoughts?

If we take a simple approach. A PW carry is about half the carry of the driver, except that the driver rolls a bit. So, if a golfer were to use a driver and PW on any given hole, it would be exactly 1.5 times the driver distance and it would be reasonable to expect that golfer to use the driver/PW for most holes that length. If it is 1.6 times the driver distance then probably driver and 9i, and can be extended up through the entire set. If this golfer is using a hybrid for more than 1 or 2 holes, then the course is probably too long. It most likely correlates better for lower handicaps is because the chances they will hit their distances is better than for a high handicaps. So, this formula works well for low handicaps, but not so well for higher handicaps.

[natureboy]

If we take a simple approach. A PW carry is about half the carry of the driver, except that the driver rolls a bit. So, if a golfer were to use a driver and PW on any given hole, it would be exactly 1.5 times the driver distance and it would be reasonable to expect that golfer to use the driver/PW for most holes that length. If it is 1.6 times the driver distance then probably driver and 9i, and can be extended up through the entire set. If this golfer is using a hybrid for more than 1 or 2 holes, then the course is probably too long. It most likely correlates better for lower handicaps is because the chances they will hit their distances is better than for a high handicaps. So, this formula works well for low handicaps, but not so well for higher handicaps.

I think you are getting hung up on the inclusion of the course lengths on the table. That was included only for reference. The only statistical correlation is between Scoring Avg / HCP and average driving distance. The USGA recommends /  encourages players with a certain average driving distance to play courses of a certain length. Generally most amateurs are playing courses too long for them to have a chance to score well and enjoy themselves.

The recovery shot fraction is intended to reflect the fraction of a clear shot lost by being in a recovery lie (with a full shot line 'blocked out') relative to an unblocked line from the same distance on the fairway. I don't understand why you are referencing which club is being used?

[natureboy]

Here's something interesting regarding trying to incorporate a 'penalty' for recovery shots.

Below is the difference in expected strokes to go (hole out) between a lie in the fairway and a 'recovery' lie at the same distance. The bottom of the curve is around the tour average driving distance of ~281 yards. The average difference value across all distances is .65 for recovery lies.

And this is the distribution of approach shots by distance from the hole for PGA in 2013. The peak is around 167 - 170 yards. The the increase in average strokes taken due to recovery lie is about .8 at that distance on the Broadie chart. So should I take that as the average 'penalty' to add to the possible fairways for pros since that is roughly the center of their shot distance distribution on the Fwy? If that is a good approach, what do you think the baseline is like for scratch and higher HCP ams? Do you think a recovery lie costs higher HCPs less sort of like the lower penalty from the rough than pros because our average shot is shorter and less precise so the smaller fractional gain in strokes wouldn't matter as much to average score?

[natureboy]

Here are two charts showing the expected average cost in strokes from a recovery lie based on the expected average approach distance according to HCP correlated average driving distance. X-axis is average score for 'Typical Course' rating of ~72. I used the PGA baseline which is certainly not the same at each distance for higher HCPs but is probably relatively close and should work for a rough estimate. For the charts below, I've basically ignored the long tail of high cost, but low likelihood recovery lies above 350 yards in the upper chart of post 67. On the this baseline, it basically costs you more of a potential scoring opportunity if your recovery lie is closer to the hole. So lower handicap players who hit farther on average would be expected to have a higher average recovery penalty for a given tee / course length.

Here is the expected penalty by HCP holding the course length constant at the 'typical' 6,500 yards. I think it makes intuitive sense that a shorter-hitting lower skilled high HCP will find chipping out sideways less of a burden to their scoring average.

Here is the expected penalty by HCP modifying the course length (and expected average approach distance based on average drive distance) per the USGA 'Tee It Forward' recommendations. It see-saws because the drop in USGA suggested course length drops off steeply to keep pace with the drop in average driving distance for high HCPs, but then runs into a low-end constraint. Pros similarly face a high-end constraint on course length so the cost of recovery lies starts climbing again as their average distance increase puts them closer to the hole on average.

One thing I saw for my own game when I calculated the two estimated baselines was that I had a very low % to recovery off the tee. This compensated my above average % penalty vs the baseline and basically describes my course conditions of deep woods and rough where a tee shot to 'other' is usually a lost cause and most of the other drives are typically not blocked out.

[Lihu]

Nicely done, this is the data I was asking about.

[natureboy]

Nicely done, this is the data I was asking about.

Great. Do you think it's okay to use the PGA recovery baseline for all HCPs or would it change shape significantly in your view like be across a lower range of shots lost from say .2 to .8  vs .4 to 1 for pros and/or a steeper / shallower slope loke with putting baselines, because ams are less accurate so shot interference matters less or is penalty more severe because they are less skilled at special shots so they are most likely only able to pull off chipping out sideways to fairway from any distance which would be about equal to costing a full shot?

[Lihu]

Quote:

Originally Posted by Lihu

Nicely done, this is the data I was asking about.

Great. Do you think it's okay to use the PGA recovery baseline for all HCPs or would it change shape significantly in your view like be across a lower range of shots lost from say .2 to .8  vs .4 to 1 for pros and/or a steeper / shallower slope loke with putting baselines, because ams are less accurate so shot interference matters less or is penalty more severe because they are less skilled at special shots so they are most likely only able to pull off chipping out sideways to fairway from any distance which would be about equal to costing a full shot?

Once you get above a 10 handicap there could be a number of reasons why a person plays so badly, and the higher you go the more reasons there are for bad play.

To me, experience factors into putting more so than handicap ? I know a lot of senior golfers who only drive about as far as my 6i or less, but some of them make 20 foot putts with great regularity (more than 3 per round).

For example, while an extreme example , I can make either 28 putts per round or 38 putts per round, while the rest of my game is more or less the same. Some days I play to my handicap or much better, and other days I can play to a 20 handicap. I feel like this is more or less experience related, simply because I can putt well on some days and miss 1 footers the next. 4 putt doubles are not uncommon for me from tap in range. I'm like, putt-putt-tap-tap double more than once per round. I'm also not really that unique, I do know people who putt like me as well.

The golfers with years of experience rarely putt that crappy.

So, even in my somewhat limited experience, putting can be erratic too, but only for people with less than some number ??? of years of experience.

[natureboy]

Once you get above a 10 handicap there could be a number of reasons why a person plays so badly, and the higher you go the more reasons there are for bad play.

To me, experience factors into putting more so than handicap? I know a lot of senior golfers who only drive about as far as my 6i or less, but some of them make 20 foot putts with great regularity (more than 3 per round).

For example, while an extreme example, I can make either 28 putts per round or 38 putts per round, while the rest of my game is more or less the same. Some days I play to my handicap or much better, and other days I can play to a 20 handicap. I feel like this is more or less experience related, simply because I can putt well on some days and miss 1 footers the next. 4 putt doubles are not uncommon for me from tap in range. I'm like, putt-putt-tap-tap double more than once per round. I'm also not really that unique, I do know people who putt like me as well.

The golfers with years of experience rarely putt that crappy.

So, even in my somewhat limited experience, putting can be erratic too, but only for people with less than some number ??? of years of experience.

I think HCP is a reflection of both physical skill and game savvy which experience (including course / green knowledge) contributes to.

It seems that with most skills that correlate well to average score there is a general tightening of the variability in variability / ranges of averages (with scoring too) as you move toward lower average scores, while there is a decrease in power, precision, and touch as you move to the high end. Seems obvious. What's not obvious is how the decrease in distance for higher HCPs (which should make recovery shots less costly) along with the decrease in precision and special shot savvy (which should make recovery shots more costly) will balance out? Add the fact that generally higher handicappers play shorter courses than low HCPs and it makes for a bit of a moving target.

Here's my rough idea of what I would expect to happen for baselines for higher HCPs. Basically for decreasing skill a recovery shot would become less costly vs. fairway and the low point would shift toward the target due to the decreasing avg driving distance.

I have mostly eliminated 4-putts but am still above my HCP in putting performance, so to have an 11 HCP you must have a great iron and/or short game or play really tough courses.