My hr is same with MadMed's. Only provide the job tile, starting date and salary.
So how could I show:
1, job similarity.
-Indicate it in the Chair letter. Also provide your recent publications, meeting abstracts, etc. since you filed your I-485.
2, permenent job. I guessed if the ELV did not mention ending date or contract. That means permement. Is that correct? Can USCIS accept this.
-In the Chair's letter or EVL, just say: "although this job is at will, the job is permanent" or say:"this job has indefinate term and Mr./Dr. XXX (you) has the expectation to continue to be employed".
3: some people mentiond the dean or director of hr should write this letter. but in my institution, most likely I can only get letter from the chairman or staff in HR. Will this be a big issue.
-Dept. Chair is enough. Also provie your HR letter.