dvcochran
Grandmaster
This gets into the heart of the differences in producing a product and offering a service.No but it puts ownus on the fridge maker to produce a product that will probably work.
Self defense never has to work.
The product will always be more repeatable because it is possible to control the variables. That is the manufacturers goal. But variables and unexpected results do exist. In the refrigerator analogy, typically several of the parts that go into the unit are manufactured somewhere else and shipped to the build/assembly facility. In the best quality controlled processes 'sheet happens' and a minor flaw in one part becomes a major flaw for the whole product. The percentage of error would be directly proportional to the QC throughout the supply chain (aka unit cost). There is very little ambiguity in the entire process. One of the main goals in manufacturing is to reduce or eliminate human error.
In a Service their are dependencies that are so broad and varying they are near impossible to track and control. The product Users are as diverse as can be imagined thus things like 'results' can be very hard to measure and specific to the user. Most services are dynamic so there are very many markers that would have to be measured. And even the markers would have to be scalar since the users are also scalar.
So, what I see in large is that most MMA service users measure value through competition and video(?) evidence. Most of the common martial arts users measure value using a broader set of rules. Effectiveness is measured in similar ways however. Resistance training and sparring and/or competition is used in every style I have experience with. Video proof, not so much.
I do expect that to change, largely because of the ease of making video and the effects of the pandemic and the way it is forcing people to change how they train. Video and distance training will be more prevalent, at least for a time.
I expect this will not be considered evidence to you however. Is the only way you see your product working is winning a match?