From the Bethesda Blog:
"We're hiring for testers in our Quality Assurance department! We tend to favor candidates with programming experience but most importantly, we want people who are fans of our games. Why would you want to work in our QA dept? I'll give you two reasons. 1. We use our QA testers as interns throughout the year. These interns are typically among our top testers, and they sit with the development team, attend meetings, and work on our games directly. So if you kick major ass as a tester here, there is a good chance you'll be a candidate for one of those intern slots.
2. When we have a job opening on the development team, we look internally first to fill them, so our QA dept gets an inside advantage."