In a phone screen, an employer interviews potential employees who appear qualified for the advertised job after the resume and cover letter are reviewed. The meetings, by phone, are conducted by one person, usually the hiring manager or a Human Resources staff member, who ask the same questions of each candidate called.
The phone screen allows the employer to determine if the candidate's qualifications, experience, workplace preferences and salary needs are congruent with the position and organization. The phone screen saves managerial time and eliminates unlikely candidates. While I recommend developing customized phone screen questions for each position, these phone screen best practices will guide you.
You want to ask enough questions during the phone screen to determine if the person is a viable candidate. Remember, you have already screened many resumes and applications to come up with your short list of applicants eligible for a phone screen. Applicants you phone screen should be your best prospects at this point in your recruitment process.
Interested in what you should be able to expect from the candidate during the phone screen? See my Phone Screen Questions.