While you're using instantaneous feedback mechanisms to see how your audience responds to your work in progress, closely monitor all the effects.
"Effect" is defined as the different ways people respond to your movie.
The purpose of this is to identify & eradicate any unwanted side effects.
And to do it in a safe and cost-effective space - before the debut of the finished product.
The earlier you catch the valid criticism,
the better your movie will be.
If one of your characters, for example, comes across in a way you didn't intend, or part of your message is being interpreted in a negative fashion, these instant feedback mechanisms will allow you to catch it early, and fix them quickly.