Blind Blade Study - #2

Most of us have strong feelings about our favorite razor blades. YMMV may apply to razor blades more than any other facet of shaving. Unfortunately, our opinions are guided by our preconceived notions of things. There is experimenter bias in every aspect of life. So long as the person shaving knows which blade is in the razor, the evaluation is biased and cannot be objective.

Recently, I completed a blinded study of 4 different blades in which I was unaware which blade was in the razor. While I was unable to identify the correct blade, I was able to easily distinguish my two favorite blades (Polsilver SI; Gillette Rubie) from the others in the study (Gillette 7 OC Black; Nacet). Others have since followed my lead and embarked on blinded studies. Poikkeus did a very thorough study in which he was able to identify all 4 blades in the study.

http://badgerandblade.com/vb/showthread.php/459344-Blade-Comparison-A-Blinded-Study


All studies have limitations, mine included. The primary problem with my study was that I used each blade on 4 consecutive days so I knew when a different blade was put in the razor. How would I do if the blades were used in a random fashion so I would have no idea if I were using the same blade on consecutive days or a different blade? This approach should be much more difficult and more accurate.

Methods:
For this experiment I limited the the number of blades to 3 - the Polsilver SI; Gillette Rubie; and Gillette Silver Blue(GSB). I would have a total of 12 shaves or 4 shaves/blade. The experiment is semi-random. Each blade would be used once during the first 3 shaves so that I could form a blinded opinion of the qualities of each blade. After that, the order was created by a random number generator. I would have no preconceived idea on a day to day basis if I were shaving with the same blade or a different blade. My wife, as with the first experiment, is my accomplice in the study.

Otherwise my methods remain similar to the first study:
1. Shave every 24 hours after a shower prep.
2. Mickey Lee PreShave Butter
3. Santa Maria Novella Barba da Crema
4. Wolfman WR1 OC
5. Soap Commander AfterShave Balm


Results:

I thought it might be interesting to present the results periodically during the study. As of today I have completed the 3 day trial in which I used each blade 1 time.

Blade A: Very smooth. Cut silently. No audible feedback. A little tugging on my tough chin hairs. Not the sharpest blade. No cuts or weepers. Very easy shave. GUESS: GSB

Blade B: Sharper than A but not as smooth. High pitched staccato when cutting hairs. Almost a clicking sound when cutting. No cuts or weepers. Guess: Gillette Rubie

Blade C: Halfway between A & B. Smoother than B but not nearly as smooth as A. Sharper than A but not as sharp as B. No cuts or weepers. Good audible feedback but at a much lower pitch than B. Guess: Polsilver SI


Even though all 3 blades were qualitatively different, all 3 gave excellent shaves and I could happily live with any of them. My sense is that, going forward, it might be very difficult to distinguish between the 3 blades in the random part of the study. A few traits stand out: Blade A is noticeable smoother than B or C; Blade B has a unique staccato sound when cutting hairs; Blade C is smoother than B but sharper (and noisier) than A. I don't know if these characteristics are distinct enough to allow me to identify each blade accurately.

My plan is to update every few days.

Bonne Chance.

What kind of prep do you use? If your beard is thoroughly hydrated, you shouldn't hear much of anything.

After three days, I think you have Blade A nailed (GSB); as for B and C, it's hard to tell. I haven't tried a Wolfman...so who know?

poikkeus said:

What kind of prep do you use? If your beard is thoroughly hydrated, you shouldn't hear much of anything.

After three days, I think you have Blade A nailed (GSB); as for B and C, it's hard to tell. I haven't tried a Wolfman...so who know?

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My routine prep is to shower and then shave immediately afterward, and use the Mickey Lee PreShave Butter(coconut oil base) before lathering. The Wolfman OC is about the same level of aggression as the ATT R2, on my face anyway. It has the loudest audible feedback of any razor I have ever used. My other razor, the ATT S2, is very quiet, almost no audible feedback. Big difference between the two razors.

Nice research. Thanks for posting.

I am now into the difficult phase of the study. The razor blade in use has been selected randomly. I could be shaving with a different blade daily, or I could have the very same blade 3 days in a row. It makes for an interesting evaluation. There are three qualities to each blade that I am focusing on: Sharpness; Smoothness; and Audible Feedback. Here is my report on Shaves 4-6.

Shave 4: Nice combination of sharp and smooth. Easy shave. Not the smoothest but no weepers, nicks or irritation. Medium pitch audible feedback. Based on the shave, I might have guessed that the blade was a Rubie, but based on the audible feedback, My guess: Polsilver SI

Shave 5: Very sharp. Not as smooth as shave 4. A few weepers. High pitched audible feedback. I am confident on this one. My Guess: Gillette Rubie

Shave 6: Sharp and Smooth. Best shave thus far. No weepers. High pitched audible feedback. Based on the audible feedback I would say that this is a Rubie, but this shave was much smoother than Shave 5, also judged to be a Rubie. Could it be that the Rubie improves after a few shaves? My Guess: Gillette Rubie


None of these 3 shaves had that buttery smooth quality that I associate with the Gillette Silver Blue. And, the GSB - or so I believe - is a very quiet blade. Based on those indicators, I don't believe that the GSB was used in shaves 4-6. To my surprise, I seem to be relying on audible feedback as the most reliable indicator. Maybe not too much of a surprise as, in my mind, the Polsilver SI and Gillette Rubie are similarly sharp and smooth blades, and they were featured in this trio of shaves. The GSB is the outlier as the smoothest and quietest blade.

Through 6 shaves I have assigned the Rubie to 3 shaves; the Polsilver to 2 shaves; and the GSB to 1 shave. As each razor is used 4 times in this study, in the final 6 shaves, I will need to assign the GSB to 3 shaves; the Polsilver to 2 shaves; and the Rubie to 1. I had better shave with a smooth and quiet blade soon(my sense of the GSB) or my predictions will be entirely incorrect.

Great methods. Look forward to following this one! THANKS!!

Shaves 6 through 9 are in the books and I am in a heap of trouble.

Shave 7: Feels exactly like shave 6. Sharp and Smooth. Audible High Pitch. While it is statistically unlikely that I had a Rubie 3 days in a row, this blade feels like a Rubie. That means I have identified the Rubie in Shaves 2,5,6 and 7, so, if correct, I am finished with the Gillette Rubie. My Guess: Gillette Rubie

Shave 8: Now I am in trouble. This blade feels exactly like the blade in shaves 6 and 7. Excellent shave. Sharp and smooth. High pitch cut. If shave 7 is really a Rubie, then so is this one. I have to call it a Rubie, but then I made a mistake somewhere along the line. My Guess: Gillette Rubie

Shave 9: Finally a blade that feels a bit different. Not quite as smooth/sharp as Shave 8. Still a very nice shave. NOT as smooth a shave as my mind wants the shave to be in order to call it a GSB. My Guess: Polsilver SI

I am in trouble. Through 9 shaves I have identified the Rubie 5 times, the Polsilver 3 times and the GSB 1 time. Since each blade could only be used 4 times, I got something wrong somewhere in the trial. Even if I confused a Polsilver for a Rubie (the two blades are very similar, on my face anyway), is it possible that the probability gods have the GSB 3 shaves in a row at the end of the trial? Possible, but statistically unlikely.

The next shave had better be buttery smooth like a GSB or I am sunk!

Stay Tuned!!

I think the Polsilver looks likely...but the Rubie/GSB race is hard to pick. You've made quite a challenge by swapping the blades after every shave. Problem is, the Rubie tends to lose an appreciable edge by shaves four and five.

Then again, the probability gods might have smiled on you. I hope you took really good notes!

In a few minutes, after I finish my morning java, I will shower and shave. Lots of tension in the air this morning. Electric! This blade had better feel buttery smooth like a GSB or I am done with. Well, not exactly done with, but you get the idea. My conclusion of this study may very well be that when selected randomly, it is impossible to distinguish between quality razor blades. We shall see.

Shave 10:

Phew! A GSB for sure. Exactly as I remember the GSB on my face. Very smooth but not as sharp as a Polsilver or Rubie. Pulling on my chin and buffing needed in a few spots to get a completely smooth shave. Maybe the probability gods are playing their games with me and the last 3 shaves will all be GSB. We shall see. My guess: Gillette Silver Blue

From my notes:

Shave 11: Smooth but having trouble with the tough hairs on my chin. Not the sharpest blade. I feel confident with this one. My Guess: Gillette Silver Blue

With one shave to go, I know that I have made a mistake somewhere. If Shave 12 is a GSB, then I have confused a Rubie and a Polsilver, not a surprising mistake. On the other hand, if I guess that Shave 12 is something other than a GSB, then I have confused a Rubie and a GSB, which would be a surprising mistake since, in my experience, the Rubie and the GSB are two distinctly different blades.

Shave 12: Definitely NOT a GSB. Sharper with a higher audible pitch. Easily handled my difficult chin. Overall a very close shave.
My Guess: Polsilver SI


After 12 shaves the breakdown is as follows:

Gillette Rubie: 5 shaves
Polsilver SI: 4 shaves
Gillette Silver Blue: 3 shaves

Since each blade was used 4 times, I have at least 1 incorrect identification. The simplest explanation is that at one point I confused a Rubie and a GSB. Possible, I suppose, but in my mind these two are the furthest apart in shave quality. It is also possible that I have made several mistakes and that my assessments are as random as the study itself. I will unlock the study key later this morning.

Stay Tuned!

Science - even pseudoscience like this experiment- is never easy. Many things can go wrong along the way.

When I broke the code this morning I knew that something was wrong. According to the code, shaves 11 and 12 were both supposed to be with a Polsilver, but they could not have been more different on my face. I asked my wife if she had changed the blade last evening between shaves 11 and 12 and she said with certainty that she had. When I showed her the code, and noted that there was no need for her to change blades between shaves 11 and 12, there was that moment of bewilderment on her face. At some point during the process she had gotten confused with the nomenclature. I assigned each blade a letter (Rubie=A; Polsilver=B; GSB=C). Each day, 1-12, was assigned a different letter. She then had to correctly transcribe the letter to the correct blade. There is no way to know exactly how many times the blades were confused. When I look over the key and compare it to my assignments, some things made no sense. For example, early in the trial the GSB was supposed to be in the razor two days in a row. I got those both incorrect believing that one shave was with a Polsilver and one was with a Rubie.. Yet, later in the trial when the GSB once again was in the razor for 2 consecutive days, I got them right both times. I have no way to make any sense of this except that there was a transcription error and the blades were not properly assigned. I will have to start all over again - after a brief hiatus.

Back to the Drawing Board!

Lovely studies! Keep us updated!

So this was a double-blind experiment...

rodmonster said:

Science - even pseudoscience like this experiment- is never easy. Many things can go wrong along the way.

When I broke the code this morning I knew that something was wrong. According to the code, shaves 11 and 12 were both supposed to be with a Polsilver, but they could not have been more different on my face. I asked my wife if she had changed the blade last evening between shaves 11 and 12 and she said with certainty that she had. When I showed her the code, and noted that there was no need for her to change blades between shaves 11 and 12, there was that moment of bewilderment on her face. At some point during the process she had gotten confused with the nomenclature. I assigned each blade a letter (Rubie=A; Polsilver=B; GSB=C). Each day, 1-12, was assigned a different letter. She then had to correctly transcribe the letter to the correct blade. There is no way to know exactly how many times the blades were confused. When I look over the key and compare it to my assignments, some things made no sense. For example, early in the trial the GSB was supposed to be in the razor two days in a row. I got those both incorrect believing that one shave was with a Polsilver and one was with a Rubie.. Yet, later in the trial when the GSB once again was in the razor for 2 consecutive days, I got them right both times. I have no way to make any sense of this except that there was a transcription error and the blades were not properly assigned. I will have to start all over again - after a brief hiatus.

Back to the Drawing Board!

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So when you don't manage to identify the blades correctly you blame your wife ?

Seriously though, looking forward to the second iteration of this blind study. AB-testing is the only way to go.

WAH wah.

Pseudoscience - a collection of beliefs or practices mistakenly regarded as being based on scientific method.

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I think this study is based on the scientific method. Maybe it's not a scholarly journal article, but it's definitely not "pseudoscience." In the world of shaving, it's almost a miracle when a controlled study comes out. And when an experimenter actually admits if an error was made. that's transparency.

Something like this happened to me when my co-experimenter made a boo-boo loading blades in a single-blind experiment. I lucked out when - like rodmonster - the easily-identified GSB came to my rescue.

These "experiments" are really good fun, but they are not easy. I recommend to everyone a book entitled Blink by Malcolm Gladwell in which he analyses how our unconscious mind interacts with our conscious assessments. It sheds a bright light on how at times the bias in our unconscious mind rule our consciousness. Put differently, our preconceived notions weigh heavily on our "objective" judgements.

I can tell you with certainty that when blind to the blade in the razor, the differences between these 3 quality blades are small. The GSB is smoother than the other 2 trial blades, but the differences between the Rubie and Polsilver are small. At times I found myself listening intently to the sound of the razor cutting the hair to gain the slightest clue.

Bobmsp commented , "So this was a double blind experiment"

Definitely the Blind Leading the Blind...........

pastic said:

So when you don't manage to identify the blades correctly you blame your wife ?

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Säg ingenting illa om min fru. Hon är Skånska.

Rod monster,
This whole thing is pretty funny when you think about it, but it takes a pretty solid scientist to admit that, and how his experiment went wrong. Didn't Thomas Edison say that he never failed, he learned 1000 ways not to make a light bulb? You keep trying and we'll keep reading. Thanks for sharing. And tell your wife that she is absolutely awesome for doing this.