How do I cope when decisions ignore the careful analysis I provide?

You can separate cause from coincidence in almost any data, a rigor most people never develop. And it wears on you to watch decisions get made as if that distinction did not matter. That frustration is the frustration of someone who cares about truth in a world that often prefers a convenient story. It is a worthy thing to be tired about, but it does not have to burn you out. Remember what is yours and what is not. Doing the analysis honestly and communicating it clearly is your work, and you can control that. Whether people act on it is theirs. When you tie your peace to their choices, you hand your calm to people who may never use it well. Where you can, work on being heard, not just being right. Translate your findings into the plain stakes a decision-maker feels, one clear sentence about what ignoring it will cost. That often moves people more than the rigor itself. And where they still will not listen, let it go, having done your part. Your job is to tell the truth clearly, not to force it to win.