If they decide to eliminate your specific function you will get laid off regardless of performance. That provides good legal protection as long as your position remains gone for a long period. Other than that personal politics is a large factor. Directors have enormous latitude to add anyone to the list. You can know you are being set up for elimination if you find everyone else is being assigned to the major projects and your work is limited to a small project. Boom, the project(s) can be eliminated with your job. and give legal cover. You can feel much better if you are assigned to major products or projects and have a lot going on and you seem overworked. Also, never complain about too much tasks and when asked claim you'd like to own everything. figure out how best to manage it. From what I've seen that's how they do it.
Reposting from another thread for good info. Original poster is @PliLhfi-oxz.