Just recently I had a  pre employment polygraph that two of the questions on it were Other than questions. I am wondering if this style of question was a control question? And how many control questions are usually asked on a test.

While following pre-test admissions, "control" questions often end up being prefaced with "Other than what you've told me..." the mere fact that a question begins with "Other than what you told me..." doesn't necessarily make it a "control" question.

For example, many examinees will make admissions when asked about the use of illegal drugs. After such admissions have been made, they may be asked during the in-test phase, "Other than what you've told me, did you ever use an illegal drug?" But this is a relevant question, not a "control."