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The Dunning-Kruger Effect and Guitar Repair
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=55897
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Author:  Woodie G [ Tue Sep 12, 2023 1:14 pm ]
Post subject:  The Dunning-Kruger Effect and Guitar Repair

Huh? Who? What? Bear with me for a bit...

With Mr. Stock back to basic functionality after rotator cuff surgery, I've been over at Greenridge a bit less often of late, but managed to catch breakfast with them this past Sunday morning. Mr. Stock handed me his phone and pointed to a text thread from one of his customers (a good player and owner of some nice 1920's through 1943 Martins).

The back-story:

- Greenridge does a presale assessment on a 0-17 a few weeks back... lovely instrument... all-original finish, original bridge which appears to have been undisturbed, and - other than nut, saddle, and frets - complete as delivered in 1938. One lighter spot behind the bridge... on inspection, one of those odd spots that pops up on mahogany-topped guitars from time to time... the last one we had seen hung in a shop window for a few decades, but only got direct sunlight for perhaps a few minutes a day during the winter months. Most notably, a very nice finish with just light play wear, the usual degree of checking on a well-cared-for instrument, and the absurd projection that 80 year old mahogany small bodied Martins seem to possess. Previous owner claimed to have had Mr. John Hall do the neck reset and replacement saddle a few years ago, so no real issues on the structural side.

- Buyer shows up with the usual internet expert-sanctioned paraphernalia and spends a few hours playing and inspecting the instrument. Offer and acceptance with a cash/no conditions sale.

- A day or so after the sale, Greenridge is advised by our customer that the buyer has visited his luthier for inspection, and that that gentleman believes the guitar to have been over-sprayed on the top and possibly the victim of a ham-handed bridge repair which required significant refinish. Specifically, that tech claims he can detect over-spray in the 0.005-0.008 inch deep scratches which were incompletely filled by all that new lacquer which - although not visible under UV and so well done as to show no obvious surface irregularities - must surely be there.

- Our customer cajoles Mr. Stock into a direct call to the buyer's luthier, who claims special expertise as a long-time automotive finisher and solid-body guitar assembler. Mr. Stock - always willing to 'wrestle the pig' - foregoes that pleasure and terminates the call with an agreement to disagree.

- Our customer is advised that if he still feels any burden in what was an unconditional, cash sale, he should suggest a disinterested third party inspect the guitar.

- The buyer calls Mr. Stock directly. After clearing a discussion with our customer, Mr. Stock covers what he considers to be the salient points of his pre-sale inspection findings and again suggests a third party with national reputation if the buyer has any lingering doubts. Mr. Stock also suggests that not every repair tech or luthier should necessarily be considered qualified to assess any and every instrument that arrives on his or her bench.

While we were having our bison huevos rancheros at the Silver Diner Sunday AM, Mr. Stock received a text from his customer that the third-party inspecting shop, selected jointly by the buyer and seller - a Retro-themed Fretted instrument sales and repair shop in Brooklyn, NY - had not only confirmed the accuracy of the Greenridge pre-sale inspection, but had offered to buy the instrument for a few thousand above the recent sale price, and considered the guitar to be one of the nicest of that marque, model, and vintage they had seen.

So what is the Dunning-Kruger Effect and why might it apply here?

Dunning-Kruger suggests that people of limited competence in some particular field of endeavor tend to overestimate their abilities and - no surprise here - very competent people sometimes underestimate their competence. That meta-cognitive task - dispassionate assessment of one's level of competence against objective performance - is linked as much to raw intellectual horsepower as to underlying personality and character. The effect is most succinctly characterized as ' incompetence often includes being unable to tell the difference between competence and incompetence.'

I'm not suggesting that people competent in a given field must always agree, but I've also seen enough botched repairs or complete misses on diagnosis of an instrument's ailments to discount the Dunning-Kruger Effect as a reason for some of the wonderfully complex messes we saw at Greenridge. My own experience in repair being somewhat limited, my sense of the industry as informed by the more experienced (and competent) luthiers around me is that a not insignificant portion of the work that any well regarded, highly competent shop and staff will see is as a result of other repair shops (or owners/'helpful' friends) mistakenly believing they are competent to carry out a repair, assessment, or other higher-level task. This results in additional monetary cost to the owner for undoing the botched repair, the added cost of repair by someone competent to execute that task, and the opportunity cost for the servicing shop.

Finally, an extension of the Dunning-Kruger Effect is the tendency for those without any degree of competence in a field to see even those of very limited competence as being highly competent. This can be readily observed by reading the comments section of YouTube guitar repair videos... my all-time favorite example of Dunning-Kruger at work is linked below.. Despite significant damage to the bridge patch during removal, destruction of the drop-in style faux through saddle, and other mayhem committed on the subject D-28, the comments are almost universally glowing in nature… but not all ;) .

In summary, if we all could channel our inner Dirty Harry (the 1973 version), we would likely see far less carnage committed in the name of luthierie.

"A man's got to know his limitations."
- H. Callahan Magnum Force

https://youtu.be/Hd63jVYTnGA

Author:  Pat Foster [ Tue Sep 12, 2023 5:46 pm ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

That was painful. The video, not your post.

Author:  Barry Daniels [ Tue Sep 12, 2023 7:09 pm ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

One thing I learned from starting various careers is that it takes a while before you start to learn how much you don't know. When you fully know what you don't know, then you're making progress and may be able to work without constant supervision.

Author:  SteveSmith [ Tue Sep 12, 2023 7:22 pm ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

Painful indeed.

Author:  Hesh [ Tue Sep 12, 2023 8:18 pm ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

Great post Woodie.

Author:  bcombs510 [ Tue Sep 12, 2023 8:36 pm ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

I’ve seen other videos where that fella is defending work he’s done.


Sent from my iPhone using Tapatalk Pro

Author:  joshnothing [ Tue Sep 12, 2023 8:58 pm ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

Great post Woodie. Why do I always experience a sense of dread when a customer calls up and says something like “my buddy - who is a master carpenter - has already done some work on this instrument …”

Author:  meddlingfool [ Wed Sep 13, 2023 3:20 am ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

https://youtu.be/AVDGgphmcX8?si=SUqk1FGciHPu5PfD

With…Dutch subtitles…?

Author:  Woodie G [ Wed Sep 13, 2023 7:05 am ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

How did you ever find Dutch subtitles? Clever, clever man.

I do love the way the script writers took what would become one of the defining movie lines from Eastwood's career and previewed it as an insult wrapped up as a compliment in the clip you linked. Then, near the end of the movie, we get the Full Harry treatment with that devastatingly effective, barely noticeable beginnings of a smirk and the delivery of the film's defining theme as mic drop dialog. Loved it then... still love it all these years later.

https://youtu.be/uki4lrLzRaU

Author:  banjopicks [ Wed Sep 13, 2023 9:15 am ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

Woodie G wrote:
Huh? Who? What? Bear with me for a bit...

With Mr. Stock back to basic functionality after rotator cuff surgery, I've been over at Greenridge a bit less often of late, but managed to catch breakfast with them this past Sunday morning. Mr. Stock handed me his phone and pointed to a text thread from one of his customers (a good player and owner of some nice 1920's through 1943 Martins).

The back-story:

- Greenridge does a presale assessment on a 0-17 a few weeks back... lovely instrument... all-original finish, original bridge which appears to have been undisturbed, and - other than nut, saddle, and frets - complete as delivered in 1938. One lighter spot behind the bridge... on inspection, one of those odd spots that pops up on mahogany-topped guitars from time to time... the last one we had seen hung in a shop window for a few decades, but only got direct sunlight for perhaps a few minutes a day during the winter months. Most notably, a very nice finish with just light play wear, the usual degree of checking on a well-cared-for instrument, and the absurd projection that 80 year old mahogany small bodied Martins seem to possess. Previous owner claimed to have had Mr. John Hall do the neck reset and replacement saddle a few years ago, so no real issues on the structural side.

- Buyer shows up with the usual internet expert-sanctioned paraphernalia and spends a few hours playing and inspecting the instrument. Offer and acceptance with a cash/no conditions sale.

- A day or so after the sale, Greenridge is advised by our customer that the buyer has visited his luthier for inspection, and that that gentleman believes the guitar to have been over-sprayed on the top and possibly the victim of a ham-handed bridge repair which required significant refinish. Specifically, that tech claims he can detect over-spray in the 0.005-0.008 inch deep scratches which were incompletely filled by all that new lacquer which - although not visible under UV and so well done as to show no obvious surface irregularities - must surely be there.

- Our customer cajoles Mr. Stock into a direct call to the buyer's luthier, who claims special expertise as a long-time automotive finisher and solid-body guitar assembler. Mr. Stock - always willing to 'wrestle the pig' - foregoes that pleasure and terminates the call with an agreement to disagree.

- Our customer is advised that if he still feels any burden in what was an unconditional, cash sale, he should suggest a disinterested third party inspect the guitar.

- The buyer calls Mr. Stock directly. After clearing a discussion with our customer, Mr. Stock covers what he considers to be the salient points of his pre-sale inspection findings and again suggests a third party with national reputation if the buyer has any lingering doubts. Mr. Stock also suggests that not every repair tech or luthier should necessarily be considered qualified to assess any and every instrument that arrives on his or her bench.

While we were having our bison huevos rancheros at the Silver Diner Sunday AM, Mr. Stock received a text from his customer that the third-party inspecting shop, selected jointly by the buyer and seller - a Retro-themed Fretted instrument sales and repair shop in Brooklyn, NY - had not only confirmed the accuracy of the Greenridge pre-sale inspection, but had offered to buy the instrument for a few thousand above the recent sale price, and considered the guitar to be one of the nicest of that marque, model, and vintage they had seen.

So what is the Dunning-Kruger Effect and why might it apply here?

Dunning-Kruger suggests that people of limited competence in some particular field of endeavor tend to overestimate their abilities and - no surprise here - very competent people sometimes underestimate their competence. That meta-cognitive task - dispassionate assessment of one's level of competence against objective performance - is linked as much to raw intellectual horsepower as to underlying personality and character. The effect is most succinctly characterized as ' incompetence often includes being unable to tell the difference between competence and incompetence.'

I'm not suggesting that people competent in a given field must always agree, but I've also seen enough botched repairs or complete misses on diagnosis of an instrument's ailments not to discount the Dunning-Kruger Effect as a reason for some of the wonderfully complex messes we saw at Greenridge. My own experience in repair being somewhat limited, my sense of the industry as informed by the more experienced (and competent) luthiers around me is that a not insignificant portion of the work that any well regarded, highly competent shop and staff will see is as a result of other repair shops (or owners/'helpful' friends) mistakenly believing they are competent to carry out a repair, assessment, or other higher-level task. This results in additional monetary cost to the owner for undoing the botched repair, the added cost of repair by someone competent to execute that task, and the opportunity cost for the servicing shop.

Finally, an extension of the Dunning-Kruger Effect is the tendency for those without any degree of competence in a field to see even those of very limited competence as being highly competent. This can be readily observed by reading the comments section of YouTube guitar repair videos... my all-time favorite example of Dunning-Kruger at work is linked below.. Despite significant damage to the bridge patch during removal, destruction of the drop-in style faux through saddle, and other mayhem committed on the subject D-28, the comments are almost universally glowing in nature… but not all ;) .

In summary, if we all could channel our inner Dirty Harry (the 1973 version), we would likely see far less carnage committed in the name of luthierie.

"A man's got to know his limitations."
- H. Callahan Magnum Force

https://youtu.be/Hd63jVYTnGA


Sounds to me like you should be making repair videos so we're not lead astray by Jerry. I like his videos, even this one. Even when he screws up, there's something to take from it. But as you say, the incompetent, me, tend to see competence where there is none. So please start sharing your work, Ill watch.

BTW, what would you do different to have a better outcome removing the bridge and saddle?

Author:  Woodie G [ Wed Sep 13, 2023 10:05 am ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

Mr. Hutchings:

There are a number of good videos posted to YouTube from members here as well as other competent luthiers, but your point is well taken. On the specific topic of a critique of the linked video, I would suggest reading the comment section and specifically those posted about 4 months ago by MDLuthier. Most of the issues I have with the video are covered in that comment.

I also suspect that if 'someone' posted the link to that video as a specific topic and asked for improvements in techniques - such as a method to avoid breaking a drop-in saddle during removal or avoid inadvertent removal of a lot of top-wood during a bridge pull - you might see some additional comments from some of the more repair-focused members here. I really have no interest in beating up on the author of those videos, who genuinely seems like an affable, entertaining gentlemen with a sincere interest in entertaining - if not always educating - his subscribers (I am not one of them, but appreciate the draw of his folksy presentation).

As to competence... it seems to me that participation here or on other build/repair sites and a willingness to ask questions suggests an interest in gaining both competence and the related ability to accurately judge one's own level of competence.

Author:  meddlingfool [ Wed Sep 13, 2023 10:22 am ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

Thank the mighty surveillance algorithms for that. Immediately after reading your post, that vid came up in my YouTube suggestions…

Author:  Woodie G [ Wed Sep 13, 2023 11:26 am ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

meddlingfool wrote:
Thank the mighty surveillance algorithms for that. Immediately after reading your post, that vid came up in my YouTube suggestions…


Yes... the preoccupation by a surprising number of powerful people with safety and stability (theirs... not necessarily ours) at the expense of anything else seems to have begot the Global Panopticon.

Author:  Skarsaune [ Wed Sep 13, 2023 11:59 am ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

Woodie G wrote:
On the specific topic of a critique of the linked video, I would suggest reading the comment section and specifically those posted about 4 months ago by MDLuthier. Most of the issues I have with the video are covered in that comment.


I took the time to sift thru the comments to find that one. Excellent and educational. Thanks for the pointer and thanks to "MDLuthier" for the knowledge.

Author:  SteveSmith [ Wed Sep 13, 2023 12:39 pm ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

Perhaps MDLuthier is a luthier from Maryland - hmmmmmmm beehive

Edit: Finally found the MDLuthier comment - wayyy down there. Comments were spot on. The first thing that got me in the video was making like it's a big deal to reglue a bridge - seriously? It just went downhill from there.

Author:  Skarsaune [ Wed Sep 13, 2023 12:44 pm ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

SteveSmith wrote:
Perhaps MDLuthier is a luthier from Maryland - hmmmmmmm beehive


Ya think? :mrgreen:

Author:  banjopicks [ Wed Sep 13, 2023 1:01 pm ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

Or Doctor of lutherie.

Author:  Clay S. [ Wed Sep 13, 2023 1:32 pm ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

Hi Woodie,
I also scrolled way way down to find Todd's (? or was it your ?) post. Brilliant way to turn a simple bridge reglue into a $675 job! If you add in the fret dress, cleaning, and set up you could probably top $1000.
I agree that some of the work in the video could have been better done, but some things- like the glue used is what the manufacturer originally used, so how critical should we be about that? If the fret dressing left the guitar with a low action without "buzzing" it may have been a matter of "wrong tools in the right hands". Some people may prefer mineral oil over wax on their fingerboards, customer preference.
I agree that it was probably the instrument being out of warranty (non original owner?) and the customer not wanting to pay the going rate for a professional shop to do the work, rather than the "authorized shop" not wanting to do it. Scoring the finish around the bridge can be a bad idea if you go beyond the finish into the wood, and probably wasn't needed with that bridge. Cleaning the grunge off the fingerboard with the razor blade looked a little excessive, but hard to judge from the video. I'm sure there are several other things I could pick apart, but nothing as bad as what I have done in my early days of luthier bodging.

Author:  Colin North [ Wed Sep 13, 2023 1:40 pm ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

SteveSmith wrote:
Perhaps MDLuthier is a luthier from Maryland - hmmmmmmm beehive

Edit: Finally found the MDLuthier comment - wayyy down there. Comments were spot on. The first thing that got me in the video was making like it's a big deal to reglue a bridge - seriously? It just went downhill from there.

Indeed, it's his YT handle. No real surprise it's spot on.

Author:  SteveSmith [ Wed Sep 13, 2023 1:44 pm ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

Colin North wrote:
SteveSmith wrote:
Perhaps MDLuthier is a luthier from Maryland - hmmmmmmm beehive

Edit: Finally found the MDLuthier comment - wayyy down there. Comments were spot on. The first thing that got me in the video was making like it's a big deal to reglue a bridge - seriously? It just went downhill from there.


Indeed, it's his YT handle. No real surprise it's spot on.


Didn't know that but not surprising.

Author:  Woodie G [ Wed Sep 13, 2023 5:29 pm ]
Post subject:  Re: The Dunning-Kruger Effect and Guitar Repair

I DID say that not all the comments were positive ;).

The story was that Mr. Morelli posted the link to the video on the Signal channel we share and - true to form - Mr. Stock ignored the post until Mr. Morelli and Mr. Verhoeven, ever the stirrers of various forms of fecal matter, suggested that they though the method shown by RSW for saddle removal was simply brilliant. Shortly thereafter, Mr. Stock's comment was linked by Mr. Morelli to the rest of us and just after that, I suggested a few edits on form to keep Mr. Stock from being made to sit in the YouTube corner.

We can agree to disagree on glues, but I believe much of whatever else was covered in the comment was simply a summary of best practices and Greenridge's preferred practices. As to business practices, I believe many fellow luthiers a) fail to realize their own worth, and thus b) undercharge. My issue with RSW was not his low prices, but rather that I believe he is overcharging based on value to the customer.

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