Dr. Dave falls victim to his own to his own experimental bias?

AlienObserver

AzB Silver Member
Silver Member
There is nothing disappointing about Dr. Daves tests, I believe they are very reliable and repeatable. You whole "discussion" with Dr. Dave seems to be raising a lot of assumptions over nothing that is already known or explained by Dr. Dave.

I respectfully disagree... He explains why kicks happen, and he recreates them.
BUT, he propose a test that produce RANDOM results. Look at the final table. There are 20 test results. He marked as "Unexpected" 9 of them. 9. Nine unexpected results. 45% of the results are unexpected... Have you EVER heard of a SCIENTIFIC experiment that PROVES something with a test that produce 45% the opposite results?? This is borderline laughable. Like seriously laughable.

Further more, my "assumptions over nothing" remain untouched by drDave in our "discussion". I challenged him more than one time to explain to me why my hypothesis on why his testing methodology is wrong and he replies with "There is nothing wrong with the procedure.", as if this is a valid scientific response. I raised some points that he has NOT already explained. All he explained was why kicks happen. These are two different things. I didn't argue with why they happen, i argued about his testing methodology.
 

Meucciplayer

AzB Silver Member
Silver Member
@AlienObserver: If you disagree with DrDave - fine. Why do I have the impression that your tone is more aggressive than necessary and that you don't take DrDave's arguments for what they are?

DrDave clearly stated that it

a) would be better if a much larger data set existed

b) there is some human error in the testing

c) he suggests that others should do their own and maybe better and/or more extensive testing.

So why don't you pick up on c) and show us your results instead of calling DrDave's results basically - trash? Do the test YOU suggested - do them 500 times with each chalk.

I believe that DrDave has more important stuff to do than chalk tests over many weeks - which would be necessary if your test regimen had to be followed on many brands. I am sure that DrDave would post your results on his website if you did it. He's done that before and he was corrected before (and acknowledged faulty tests) but just throwing in the assumption "DrDave's tests are wrong" is not something worthwhile. IMHO they are the best YET on cling WRT different chalk brands available which does not mean that a more extensive and better test would not be possible. So why don't you just invest your own time to show us how you do it better instead of letting off steam? Oh - and please show us how you do it on video.

Right now my impression is that your own biased feelings towards your brand of chalk are not met by DrDave's experiment and this causes your criticism in that harsh way.

Improve on the testing and show us.
 

AlienObserver

AzB Silver Member
Silver Member
@AlienObserver: If you disagree with DrDave - fine. Why do I have the impression that your tone is more aggressive than necessary and that you don't take DrDave's arguments for what they are?

DrDave clearly stated that it

a) would be better if a much larger data set existed

b) there is some human error in the testing

c) he suggests that others should do their own and maybe better and/or more extensive testing.

So why don't you pick up on c) and show us your results instead of calling DrDave's results basically - trash? Do the test YOU suggested - do them 500 times with each chalk.

I believe that DrDave has more important stuff to do than chalk tests over many weeks - which would be necessary if your test regimen had to be followed on many brands. I am sure that DrDave would post your results on his website if you did it. He's done that before and he was corrected before (and acknowledged faulty tests) but just throwing in the assumption "DrDave's tests are wrong" is not something worthwhile. IMHO they are the best YET on cling WRT different chalk brands available which does not mean that a more extensive and better test would not be possible. So why don't you just invest your own time to show us how you do it better instead of letting off steam? Oh - and please show us how you do it on video.

Right now my impression is that your own biased feelings towards your brand of chalk are not met by DrDave's experiment and this causes your criticism in that harsh way.

Improve on the testing and show us.

I have to agree with you on some of your points, but disagree on others.

While yes, drDave has stated that "would be better if a much larger data set existed" and all the other things you said, he did avoid to comment on my hypothesis on why his testing methodology on this particular subject was wrong. I didn't just say "your test is wrong", I sat down, thought about it and pinpointed the exact reason why I believe this is wrong and tried to explain it as best as I can. So if he does not comment on this, i understand that he can not defend his test. If what I'm saying is valid then his test is wrong and doing a test that is wrong more times will produce more wrong results.

"I believe that DrDave has more important stuff to do than chalk tests over many weeks - which would be necessary if your test regimen had to be followed on many brands. "
I can't agree with you on that one. Is he an "scientific instructor" and a YouTuber or not? If he has "more important stuff to do" then he has more important jobs to do. In fairness, I believe he indeed has a more important job to do, yes, but he himself is the one who tries to be an instructor and a person who does scientific tests on pocket billiards, there is no one forcing him to do this. If he has more important stuff to do, then he shouldn't make videos like "10 things
you do wrong in pool" and focus on his real job. You either are a scientific pool instructor or not.
I'm a musician. I make money from it. If someone complains that I played something wrong and shows me the sheet of music, I can't just say "i have more important things to do". Are you here to do the job or not?

I basically agree with you only on the "then why don't you do it yourself" point. But again, you are half right IMO. I could do the test myself, yeah, but again, I'm not the one who has a YouTube channel and portray myself as a scientist who takes physics principles to explain why and how things work on billiards and make educational videos. He does that.

Am I bias? In reality no, but I get why you would think that. Would it help if I pointed out that my discussion with drDave happened 7 months ago and by then I hadn't even seen a taom chalk in person? While this is true, again, I can understand why you wouldn't believe that.

BUT, even if I am biased, this does not change the fact that I have made a clear hypothesis which is based on physics, geometry and logic, and no one has commented on in. No one has said that "you know mate, you are wrong because on your hypothesis you said this and this applies only when the room temperature is x y z", something, something that doesn't make sense in my hypothesis. No one has actually taken the time to think about it, and pin point my mistake, like I did with his test.

Again, you are saying that a test that produce 45% the opposite results is a valid test that proves something... I don't care if my chalk is better than others, I don't care if it is the worst, I do care that so many people take for a fact a test that produce 45% wrong results, and defend it!!! This is ridiculous...
 

alstl

AzB Silver Member
Silver Member
Have you been from Tuscon to Tucumcari?

Tehachapi to Tonopah?

:cool:

I probably have when I was a kid. My Dad was a construction worker and we moved constantly 15 schools in 12 states. Tucumcari was also the toughest school I was ever in. I was glad to move out of that place.
 

hang-the-9

AzB Silver Member
Silver Member
I call shenanigans on the being a good editor part, your post is at least twice as long as it has to be with a ton of words and detail irrelevant to the actual point.

Let me sum up.

Dr Dave moves his cue during the stoke and therefore the resulting observation is invalid.

Now that's editing.
 

deanoc

AzB Silver Member
Silver Member
This stuff is beyond my mentality
I did enjoy watching Dr Dave explain something about comparative deflection one time

First he hit balls at a target spot.
then he moved his cue to the left or right of center,paralel to the dead center

All cues deflected pretty much,and pretty much the same
Then he began to test using pivot technique

From what I understood the different cues were tested with a certain amount of side (say one tip)

Someway or another the Revo (I believe) was showed to require a shorter bridge to cue ball length say 15 inches compared to 17 or so for the others

As I say,honestly this is beyond my understanding


The point I am trying to make is that Dave was using a different length on each cue to obtain the best results

ie the test varied the length from hand to cue ball was considered the best for deflection purposes and easiest to operate
assuming I understood his message


My conclusion is that his apparent inconsistency to the observer can be explained by this
previous procedure and is to be understood as part of the test

So each part of his test may be assuming that his previous procedure ( adjustment by pivoting to impart side) is in effect
even though he does not explain everything each time and we may think we have caught him in an inconsistency when
in fact there is no inconsistency in the testing
 
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deanoc

AzB Silver Member
Silver Member
These post are so confusing I

would like to ask one question.

Am I correct in understanding that the initial thread was written by
a fan of Dr Dave's work and poking good matured fun at what
he assumed was an inconsistency ?

the way one friend does another with humor?
Possibly even with thankfulness or admiration?

Slim Limpy only,not the subsequent replies
 

Rtoron

AzB Gold Member
Gold Member
Silver Member
I saw this Dr. Dave video previously to reading your article. I thought he was steering the shots also. Whether intentional or not it did appear that way to me also. I then read your article and again reviewed the video with the same conclusion. I have to agree with you.
 

berko

Aggressively passive
Silver Member
I probably have when I was a kid. My Dad was a construction worker and we moved constantly 15 schools in 12 states. Tucumcari was also the toughest school I was ever in. I was glad to move out of that place.

Sorry, just goofing around





Willin'

Little Feat

I been warped by the rain, driven by the snow
I'm drunk and dirty, don't ya know,
And I'm still willin'
Out on the road late last night,
Seen my pretty Alice in every head light
Alice, Dallas Alice
I've been from Tucson to Tucumcari
Tehachapi to Tonapah
Driven every kind of rig that's ever been made
I've driven the back roads so I wouldn't get weighed
If you give me: weed, whites, and wine
And you show me a sign
I'll be willin' to be movin'
I've been kicked by the wind, robbed by the sleet
Had my head stoved in, but I'm still on my feet
And I'm still...willin'
Now I smuggled some smokes and folks from Mexico
Baked by the sun, every time I go to Mexico
And I been from Tucson to Tucumcari
Tehachapi to Tonapah
I've driven every kind of rig that's ever been made
I've driven the back roads so I wouldn't get weighed
And if you give me: weed, whites, and wine
And you show me a sign I'll be willin' to be movin'
 

Bob Jewett

AZB Osmium Member
Staff member
Gold Member
Silver Member
I literally proposed a test in my youtube comments.
One of your comments is:
" When 2 balls hit, their contact point is 1 single geometric point, (in perfect conditions). So if there is chalk on this exact point, there will be a kick."
You might be interested to know that the contact patch between balls when they collide (both balls actually flatten) is up to 3mm or so. It is not a point. The diameter of the contact patch depends on the speed of the shot.

Your proposal was to shoot thousands and thousands of shots. Among serious researchers, the proposer of a new experiment is usually expected to try the new experiment himself.
 
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dr_dave

Instructional Author
Gold Member
Silver Member
Dr. Dave falls victim to his own experimental bias?

I didn’t want to add this to the thread that originally sparked me to write this because it would be off-topic but in the thread “Shaft Comparison” by Rico, Dr. Dave wrote:

If you want to know the reasons CF shafts are a growing trend, see:

NV J.12 - How to Select a Pool Cue, Cue Ball Deflection, Carbon Fiber, Revo vs. Cuetec

Enjoy,
Dave

Ok, I’m calling a “Gotcha” on you, Dr. Dave.

First, let me state that I taught myself how to play pool with your “Illustrated Principles” book. My copy has plenty of use on it. Only recently have I begun to investigate your website, however. I’m very detail oriented, so I notice some things that might just be passed over by others on occasion.

I just reviewed your video and the comparisons of LD shafts and the differences of the Cuetec and Revo shafts that you directed us to in your earlier posting in Rico’s thread. I hadn’t seen that one before.

I, Pool Sleuth Slim, immediately noticed something odd in the clip and re-watched the segment of the clip that that I was calling into question. Says I, I says to myself, “I thinks I’s gots somethin’ here”. Or at least so I says to myself, says I.

In order to determine whether my highly refined sleuth instincts were oriented properly, I went to a couple of your other clips to assure myself I was on the correct path (puns intended).

First, I took a look at both you and Bob taking ordinary straight shots in your videos. Every shot I saw had you and Bob demonstrating straight follow-through. No exceptions. I was reminded of what Phil Capelle stresses in his books, “All shots are straight”. I went to your video NV 2.6 – “Steering follow through” here:

https://billiards.colostate.edu/normal_videos/NV2-6.htm

where you say, “Inexperience players often suffer what is called stroke steer . . . It does not have good consequences, unfortunately.”

I bet it doesn’t.

So now, Wannabe Pool Hustlers, Chronic Pool Story Exaggerators, Imaginary Six-Pack Wonders, Pool Cue Pushers and Dedicated Rail Birds, I direct your attention to the video in question:

https://billiards.colostate.edu/normal_videos/new/NVJ-12.htm

Pay attention to Dr. Dave’s cue alignment on his test shots starting at 1:58 – 3:47. After stating in the video that his (Dr. Dave’s) goal is to “[keep] the cue parallel to the aiming line” on the shots using deflection, you will notice that the cue steers off center directly in line with the cue ball’s deflection with the most off center steering occurring when shooting with the Player’s cue. Stop the video at 2:59 and examine the shaft alignment with the Player’s cueball deflection alignment. Dr. Dave’s shaft is maybe 30 degrees off center. The shaft’s alignment with the cueball’s deflection is also almost perfect when testing the other shafts. Now watch the “Aim Compensation with Sidespin” demonstration beginning at 3:22. Notice the difference? Dr. Dave’s cue has near perfectly straight follow-through.

So I says to myself, you know, I says, “Listen, the odds of Dr. Dave’s near perfect shaft alignment with the cueball deflection as seen in this demonstration being coincidental or haphazard seems to me practically nil.” So anyways that’s what I says to myself after saying that to myself.

So, after consulting the staff Doctors of Psychoanalysis at the offices of Looney, Tooney, Head, and Shrinker with all my accumulated evidence, we have come to the conclusion that Dr. Dave is indeed unconsciously attempting to steer the cueball in that video in order to affirm the predetermined results of his previous testing of these shafts.

Now, this is not to accuse Dr. Dave of any malicious intent in his demonstration. I don’t question the results. He obviously had already tested these shafts out and was just reaffirming knowledge in this video he had already acquired from previous testing. I find it rather humorous that Dr. Dave in his videotaped shooting demonstration would fall victim to his own experimental bias, even if the results are accurate.

Either that or Dr. Dave is really one of the “inexperienced players using stroke steer” whom his other video informs us about.

Prosecution rests.

Defense may now offer its rebuttal.

Your response, Dr. Dave?

As always,
Pool Sleuth Slim
FYI, here are pertinent comments from the YouTube video description:

NOTE CONCERNING FOLLOW-THROUGH: During the first set of tests, hitting the CB straight up table with parallel english, my follow-through was not very straight. However, I think I hit the CB accurately, with the desired tip position and in the desired direction. The crooked follow-through happened mostly after the CB was gone, so the shots still had the desired outcome. Also, when I did the filming, I did a large number of shots with each test and with each cue, and only included the shots that seemed to be the most-representative "average" shots for each, so I am fairly confident the relative comparison is accurate (i.e., my stroke might have been bad, but I think it was bad in a consistent way for the shots I included in the video). Regardless, the "natural pivot length" tests starting at the 4:22 point in the video provide a much more reliable way to test and compare shafts, so please refer to that instead. Nonetheless, the results of the two sets of tests were consistent with each other.

UPDATE CONCERNING FOLLOW-THROUGH: I did some additional filming to help me diagnose what was causing the non-straight follow through, and I finally figured out what was causing it (after playing the video back in slow motion). When the tip hits the right side of the CB, a sideways force pushes the shaft to the right against the thumb of my open bridge. Then the cue bounces to the left off the thumb causing the follow through to veer left, but the CB is long gone by the time this happens.
 

deanoc

AzB Silver Member
Silver Member
I know there is a lot of spirited argumentation on Az

I am very appreciative of the reports and demeanor of Dr Dave

His comments are more technical and therefore not real helful to me,
but I freely accept the blame for this

I have been interested in hearing your comments,they actually seem to confirm what i was trying to say earlier

i applaud your work with pool,I am very impressed
 

Patrick Johnson

Fish of the Day
Silver Member
I saw this Dr. Dave video previously to reading your article. I thought he was steering the shots also. Whether intentional or not it did appear that way to me also. I then read your article and again reviewed the video with the same conclusion. I have to agree with you.
Did you read the explanation I gave in post #2 of this thread? Or AtLarge's link to Dr. Dave's explanation in post #6? Or Dave repeating the explanation in the post above? Do you have some reason to doubt it?

pj
chgo
 

hitman22

AzB Silver Member
Silver Member
Some day you all might transcend all for glory or still keep looking for elusive BS ....
 

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Bob Jewett

AZB Osmium Member
Staff member
Gold Member
Silver Member
Dam it!

This would explain why my new angstrom delineated aiming system has never worked well.

It is off by many orders of magnitude.
You must have pretty good eyesight to be working down to angstroms. That will still be useful but you have to set up for the center of the contact patch. A complication is that the center of the contact patch moves while the balls are in contact. That is, the line of centers of the balls turns some during the contact as the cue ball in effect goes slightly through the object ball.

Related to which, one of the chapters in the Sports Gene is about baseball and it turns out that a lot of ball players and especially top hitters have visual acuity down in the 20/10 to 20/8 range. This is partly related to the density of receptor cells in the retina as I recall. Some people can just see better than others.
 
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