BTSA = Beginning Teacher Support and Assessment Most teachers with their initial (preliminary) credential need to go through a two year program (called by some "induction") that provides a mentor and is meant to encourage growth through reflection by the new teacher. Completing BTSA leads to a clear credential, which is renewable every 5 years for a fee, but no more hoops. Some private, parochial and charters do not offer a BTSA program, so people have to pay to do it with a university. Most (all?) public school districts have a process in place which allows their new teachers to complete BTSA. One problem with the very tough job market CA has had for the last several years, is some people with preliminary credentials were running out of time to complete BTSA. You have five years to finish it, and it is hard to manage without having a teaching job.