According to USCIS, the “good cause for termination” clause has been an important issue when adjudicating EB1-Outstanding Researcher or Professor petitions. This clause should be included in employment offers to ensure that the job is not “at will” employment.

However, an USCIS’ memo in 2006 indicated that, EB1-OR petitions should not be denied simply because the offer of employment is lacking a “good cause for termination” clause. Therefore, the employment "at will" is also accepted by USCIS for EB1-Outstanding Researcher or Professor petitions, since USCIS considers it is a common business practice to have such clause in the job offer letters. 

If the employment "at will" cause is in your job offer, then in the EB1-OR petition, your employer needs to demonstrate that your research position will have “an expectation of continued employment.”