Post #1683: The Great Razor Blade Experiment, stopping early for benefit.

Posted on January 14, 2023

 

This is part of an ongoing series to test various internet-based suggestions for extending the life of a razor blade.  You can see the background for this in the Post #1672.  The setup for this experiment is given in Post #1677.  Start of experiment is given in Post #1679

Stopped early for benefit.

The science of controlled clinical trials includes the concept of “stopped early for benefit”. 

Clinical trials typically compare two or more groups, randomized to receive different medical treatments.  By comparing the outcomes for the groups, you can measure the extent to which the treatments mattered.

Normally, the duration of a clinical trial will be specified at the outset.  For example, you might decide to follow individuals who did and did not receive a COVID-19 vaccine for half-a-year.  You specify the duration at the outset for many reasons, not the least of which is to avoid giving the researcher the opportunity to game the results by picking a stopping point that makes a particular treatment look good.  (You typically also need to specify duration in order to do a “power calculation”, that is, to check whether you have a big enough sample to measure the outcomes you are interested in.)

But, sometimes, a treatment works so well that it would be unethical to withhold it.  In those cases, a clinical trial may be “stopped for benefit”.  That is, the benefits of one treatment are so large, and so obvious, compared to the alternatives that a) you know your answer and b) if you didn’t provide it to all your patients, you would be subjecting them to significant risk of harm.

My face tells me I ain’t gonna make it to ten shaves.

Source:   Barbasol.

I figured I’d test whether softening your beard extended the life of a razor blade, by making ten shaves with the same double-edged blade.  One side of the blade, using my usual Dove soap for the shave, on one side of my face.  The other side (of blade and face), using Barbasol, which, among other things, contains beard softening agents.

And, much like the fellow in the Barbasol ad above, my face is talking to me.  Half of it — alternating each day, mind you — is saying “ouch”.

I am hereby stopping this trial for benefit.  Three shaves with soap and I’m ready for a new blade.  But three with Barbasol, and I’m just getting warmed up.

I’m going to tough it out to five shaves.  But no further. Practically speaking, it doesn’t really matter whether I’m literally getting less blade wear, or whether the higher comfort factor from Barbasol over soap is allowing for additional shaves on a given blade.  Either way, I can clearly get more shaves out of a blade when I use Barbasol.

I’ll check the edge and test the sharpness after five shaves.  But from a practical standpoint, I already have my answer.  The rest of this phase of the experiment is academic.

Stopped early for stupid?

OK, that’s not a concept in clinical trials.  But maybe it should be, in some cases.

Separately, my rustproof stainless steel blades are … wait for it … totally and utterly failing to rust.   So that part of the experiment is now akin to watering a plastic house plant.  Useless but harmless.

So I’ll keep that up for a few more days yet.  But I’m pretty sure I know the answer to that one as well.

I mean, think about it.  Do you wipe off your stainless-steel kitchen knives, for fear that water is going to make them dull?  If no, then I think you already know the practical answer about whether you need to dry your stainless-steel razor blades after each shave.

But I’ll keep watering these for another week or so.  And then, I’m pretty sure I’ll end up demonstrating that keeping them either continuously or periodically wet, whether new or used, has no impact on sharpness and shave quality.

The short answer is that if your blades don’t rust, then wiping them off after each use confers no particular advantage.  But I’ll go through the motions to prove that.

This is, after all, Science.  Sometimes, as with Barbasol, you get surprised.