If the system is up front about what the inputs are then I think most of the problems evaporate. The user doesn't need to understand the math behind how 0-5 s

If the system is up front about what the inputs are then I think most of the problems evaporate. The user doesn't need to understand the math behind how 0-5 star ratings get translated into movie suggestions, if the user understands that the star rating is the input and not dumb implicit stuff like dwell time, then the user will have a more agreeable experience with the system. I've recently created a system for assigning tags to files. The system recommends tags that might be applicable to a file given what the file is already tagged with and what other files are tagged with. There are no other inputs, I'm not trying to extract information from the filename or running image recognition on images or anything like that. It's straight forward multi-label classification similar to a naive bayes spam filter. Straight forward but effective; the relevant tags are often at the very top of the suggestions list. I've had a few non-technical users try it out and so far the response has been very positive. They don't know how the tag suggester works. All I told them is that when they enter a tag, the suggestions for other tags are refined. If all they know about the algorithm is what inputs it takes, they're comfortable with it. If the inputs are well defined, then the whole thing becomes "just a machine". Similar to how a non-technical user doesn't need to understand how magnetrons work to be comfortable with microwaving some popcorn, a user doesn't need to know how machine learning works to be comfortable with a program employing it. Just make sure they understand the general relationship between the buttons on the front and what the outcome is going to be. Don't make a microwave that tries to be clever by turning up the power if the user is standing impatiently in front of it. If you do that, the users will start to get paranoid/superstitious about the microwave (and rightfully so!)