It’s so easy to assume things when you’re interviewing. You find out that you have something in common with the interviewer, you meet all the requirements, the feedback is positive, you’re relaxed. You end thinking you might actually get an offer.
Before you get your hopes up, find out if there’s someone in the company going after the position.
While there aren’t statistics on this, the odds are good that if someone inside the company is applying for the job, s/he’s going to get it. Make sure you ask not only how many people are interviewing, but if there’s an internal applicant.