My experience (I have been involved in salary/bonus/raise decisions) is usually salary is set based on the necessary amount to secure the engineer, which usuall

My experience (I have been involved in salary/bonus/raise decisions) is usually salary is set based on the necessary amount to secure the engineer, which usually means at least their previous salary + compensation for taking the risk of a new environment with new people. I should note that I've mostly worked with small companies where these decisions are somewhat ad-hoc and non-standardized. Raises and bonuses are based on how much can keep the engineer motivated and prevent them from looking for new work (I don't want to sound too cynical here, I think when it comes to measuring how much someone deserves in a raise/bonus is essentially how much it takes to keep the engineer providing this level of work, more or less) (based on management's assessment, and often constrained by general salary policies). That's how I approach these discussions in broad terms, although keeping an engineer motivated and preventing them from looking for new work are not simple things to analyze