Interview phone screen calls will generally be made impromptu, that is, without prior notice to the candidate. However, you can email the individual ahead of time to alert them to the time frame you plan to call or to prearrange a set time based on their availability. Be aware you have now opened a line of communication that you may have to manage going forward, at least initially.
The phone screen interview should be conducted by one individual—most likely a designated (and prepared) HR representative or a recruiter/staffing specialist. Having more than one company person on the call tends to create confusion due to the nature of phone calls, plus you're tying up more personnel resources than are needed at this point in your interview process.
The phone screen interview will probably last between 20 to 40 minutes depending on the amount and depth of information you have planned for this screening call. A set of structured questions should be prepared ahead of time, written out in a simple interview guide format that includes space to take notes and record impressions. This format could include the following:
How did you learn about this position?
Why are you currently looking for a new position? And walk me through the reasons for your last (#) of job changes.
What are the key skills and recent experience you have as they apply to this position (assuming the candidate has some knowledge of the position from the advertisement or job posting descriptions)?
Briefly walk me through your accomplishments in your current and previous positions (ask this in relation to positions held that apply to your organization's business/industry).
Why does this position interest you?
If there appears to be good interest in the candidate explain your interview process going forward, and ask about the candidate's availability to meet as the next step.
If you email the candidate ahead of time (i.e., to arrange a time frame to call), think about including a brief overview/expectation of the phone call, but not including the specific questions. In this early phase of your process, you are looking for some level of "thinking on your feet," clear responses from the candidate indicating their verbal communication skills, and a sense of their interpersonal skills. The email could include the following:
John, I plan on calling you on Monday between 2:00 & 4:00 to introduce myself and National Bank to you. I would like to briefly cover your work history and key areas of your work experience to determine how they relate to the basic requirements of the position for which you applied. I can also answer a few questions you may have regarding this position and our environment at National. If this time is not convenient for you, please let me know several alternatives that would work for you.
From an EEO perspective, there is always a slight risk, even with a phone call, of a personal prejudice against race, place of origin, or sex that can sometimes be determined on the phone. However, in this initial phase of your process, these prejudices will tend to be minimized on a phone call over a face-to-face meeting—you're not laying eyes on the individual. The overall caution for your entire interview and selection process is to have everyone involved be trained to exclude illegal questions and personal biases that would fall into a liability category. The best approach for this is preparation—with targeted information (i.e., skills, competencies, traits), legally defensible questions, and a fair and consistent process that everyone follows. Keep in mind this interview step is very common and used every day by many, many organizations. The EEOC certainly knows this, and they expect a well-prepared, consistent, and documented process where all participants have a thorough understanding and will follow the process.