A PhD in Engineering represents the terminal degree in this field, and as such it opens the door to the widest range of careers and highest salaries available in engineering. Often a PhD will be either research- or practical-based. Engineers who focused on research for their PhD often stay within the education system and become professors at universities, working with students as well as in labs conducting their own research. A more practical-based PhD in Engineering will allow graduates to pick and choose from top engineering jobs in their specialty.