I apologise, it's clear I've not struck the right chord. I'd hoped that highlighting the distance between opinion and evidence might defuse the conflict. Perhaps I've inflames it instead.
Well, I agree with your main point. You aren't going to be able to completely reduce the concepts "mild" and "aggressive" to a single reliable objective statistic. There will always be a variety of subjective reactions.I apologise, it's clear I've not struck the right chord. I'd hoped that highlighting the distance between opinion and evidence might defuse the conflict. Perhaps I've inflames it instead.
To confuse the matter further, applying the term 'aggressive' to a razor is somewhat subjective. How aggressive a razor feels depends on parameters beyond the razor, like skin type or beard density for instance. A razor that's aggressive for me is mild for someone else, but these terms don't tell us anything unless we have the same face, technique, lather, etc.
Part of the process of defining a razors parameters is to define the terminology used. Subjective terms like 'rigid' and 'aggressive' need to be separated from objective terms like 'guard span', 'neutral blade angle' and 'blade exposure'.
I think the best we could hope to achieve in this discussion is to define correlation - as distinct from causation - between objective measurements and subjective outcomes. Something like "May suits users with a preference for very aggressive razors" for example.
In summary, @weekly is just as correct as anyone. However, equating subjective outcomes directly to a single objective measurements is also flawed. Perhaps we can agree that without a database of measurements, preferences and information regarding users, making any conclusions about this now is a little pointless.
I apologise, it's clear I've not struck the right chord. I'd hoped that highlighting the distance between opinion and evidence might defuse the conflict. Perhaps I've inflames it instead.
Yes, I've long since learned that hard data and statistics, though highly useful, only take one so far. A scientist or engineer could assign precise, objective definitions to terms like aggressive and rigid, but the outcome on one's face would still not be entirely certain. I was cautioning @weekly against too much reliance on blade gap or any other single measurement, and that was @ShavingByTheNumbers' point too, I think. I don't think anyone is saying you can completely reduce the performance characteristics of even the relatively simple safety razor to a series of numbers, at least not as a practical matter. You can see from his posts that @ShavingByTheNumbers understands that very well.
Well, I agree with your main point. You aren't going to be able to completely reduce the concepts "mild" and "aggressive" to a single reliable objective statistic. There will always be a variety of subjective reactions.
As it showed in the beginning of this thread, the gap has nothing to do with aggressiveness. It will allow for more angles to be used with the razor since the base-plate is further away.
Blade exposure will always determine a razors aggressiveness.
To me this is another example of trying to relate a single objective measure to a subjective outcome, precisely the opposite opinion to @weekly in fact. Both positions are right, neither position is wrong. In my opinion blade gap has a relationship to guard span, which makes a difference to my shave. Making a statement of fact based on your opinion/experience may not be true for everyone.As it showed in the beginning of this thread, the gap has nothing to do with aggressiveness... Blade exposure will always determine a razors aggressiveness.
A large blade gap can be perceived as aggressiveness. I use to use a Parker 94 which had quite a large blade gap and it did feel somewhat aggressive. As was said earlier in this thread each person will perceive how it shaves in his own way.
@ShavingByTheNumbers I think we're on the same page here. A model is exactly what I'm getting at when I say correlation. We can model the relationship, possibly quite well as you suggest, but that doesn't necessarily relate causation for any given measure or group of measures, not without measuring individual effects of each parameter. The fact that you've not published your model indicates to me that you may hold the same reservations I do?
@ShavingByTheNumbersI suppose the thing that frustrate me a little about this conversation is people trying to make a point. Making a point is really about opinion, while objective measurements stand on there own and require no defense. That we're debating anything at all is in itself an indication of opinionated defense of a position. The truth is it's own defense.
@ShavingByTheNumbersOn the topic of 'blade gap' as an useful objective measure of performance, this has really been used as a crutch to at least identify something that can be used as a point of comparison between razors or settings or a single razor. If a manufacturer advertised a list of sixteen parameters it would be difficult or impossible for the consumer to make a decision based on the data. So, we list one measurement, flawed though it may be, to assist in the decision making process. There's probably some correlation between perceived aggressiveness and blade gap, perhaps a lot, I don't know, but I think we can agree it's not the whole answer. As a direct measure of performance I think guard span has more meaning that blade gap because it's oriented with the shave plane.
Right... think I missed that bit earlier. What sort of sample set do you need to validate? I can only make a small contribution here, bit amongst the B&B membership I'm sure it would be simple enough.I get what you're saying about not confusing correlation with causation. My aggressiveness model doesn't just come from some statistical analysis. The model is physically realistic, based on physical reality and reasoning with respect to cause and effect and fit to the small amount of available data.
And that's the difference between scientists and the rest of the population really. I couldn't care less if my opinion is correct or not. Provided the evidence is valid I'm more that happy to be wrong.I think that we're on the same page, too. We're having a lively discussion, not an argument, right? There are definitely differences of opinion here, and in the end, I hope that the truth wins out, whether I'm right or wrong about it.
Reading between the lines a little here, can I assume the model is based largely on these three dimensions? Perhaps we should be recommending a shift towards these three and away from blade gap?Blade gap is an easy parameter to measure, and since it is only one parameter, it makes razor comparison easier but largely inaccurate since blade exposure is so important. You're right that guard span has more meaning than blade gap with respect to actual performance. I think that each of us could get used to looking at three parameters (blade exposure, guard span, and blade angle) rather than one (blade gap) to find out what works best for each of us, and since we ignore information that we don't care about or don't want to deal with, plenty of us could just ignore the extra parameters.
See point above about the difference between scientists and normal people.However, fail to understand why anybody would object to factual reporting of metrics irrespective of belief in their influence on performance. Not being flippant nor churlish but utterly confounded at the hostility.
Could you define guard span and cap span? They are measured from the blade cutting edge to exactly where?
Is clamp distance the distance from the blade cutting edge to where the blade is clamped in a vise like fashion by both the cap and the baseplate?
One end of the free-end distance is the blade cutting edge. What is the other end exactly? What is the importance of the free-end distance?
I may have a few more questions, but without knowing the answers to the questions I just asked I don't know.
Your illustrations and the work and thought which went into all of this great stuff is greatly appreciated.
Speaking solely for me, coming from hard science education and numeracy based professional experience, this work is highly appreciated. If it is duplicative of previous efforts, apologies for ignorance of their existance.
While there certainly exist intangible elements of performance, have found in every realm encountered to date: if it can’t be quantified, it is either due to lack of understanding the proper definition/methodology or it is extraneous but can not presume to speak for others.
However, fail to understand why anybody would object to factual reporting of metrics irrespective of belief in their influence on performance. Not being flippant nor churlish but utterly confounded at the hostility.
Right... think I missed that bit earlier. What sort of sample set do you need to validate? I can only make a small contribution here, bit amongst the B&B membership I'm sure it would be simple enough.
And that's the difference between scientists and the rest of the population really. I couldn't care less if my opinion is correct or not. Provided the evidence is valid I'm more that happy to be wrong.
Reading between the lines a little here, can I assume the model is based largely on these three dimensions? Perhaps we should be recommending a shift towards these three and away from blade gap?
I really want to get the camera out and work up some data on what I have now, just to satisfy my own feeling on what parameters are meaningful to me.
See point above about the difference between scientists and normal people.
Great work, @ShavingByTheNumbers, and this last observation is on point, I think. Of course, because among other things, our faces and necks are not identical and not made up of flat, rigid surfaces, I don't expect these three parameters, or any other set of parameters, to tell the whole story. But they would be useful, and likely more useful than blade gap alone, I think. With more data from you, maybe we'll get to put your theory to the test.I think that each of us could get used to looking at three parameters (blade exposure, guard span, and blade angle) rather than one (blade gap) to find out what works best for each of us, and since we ignore information that we don't care about or don't want to deal with, plenty of us could just ignore the extra parameters.
Great work, @ShavingByTheNumbers, and this last observation is on point, I think. Of course, because among other things, our faces and necks are not identical and not made up of flat, rigid surfaces, I don't expect these three parameters, or any other set of parameters, to tell the whole story. But they would be useful, and likely more useful than blade gap alone, I think. With more data from you, maybe we'll get to put your theory to the test.
As usual, @ShavingByTheNumbers , your work is encyclopedic. Thanks for putting in all the effort, I'm impressed every time.