From: Staffing Talk (edited)
These 6 questions will get you an accurate Job Description.
1. What single statement best describes your role?
2. Which activities absorb most of your time?
3. What challenges prevent your best work?
Translation: What gets in the way of you doing your job?
4. What single statement reveals your vital purpose to the organization?
Translation: What is the most important thing that you do?
5. Which of your contributions have the greatest value to the organization?
Translation: What's the best example of your work -- related to your key job function?
6. What are the hidden challenges of delivering this value?
Question: How is this different from Number 3?
Comment: It's presumed that you are going to get this information from someone who is currently in the job. This probably means that her boss, the hiring manager, would not be able to tell you.