Follow-up phone calls certainly aren’t out of the place, in particular if you have made it to the short-list, and if you have other opportunities that you are trying to manage. Here are some factors to consider:
Timing: It is always a good idea to understand where possible, where you are in the timing of a recruitment process. Candidates that get in early, often have to wait longer. Sometimes, you need to be patient (while of course continuing to search).
Frequency: There is a fine line between appropriate follow-up and being a pest. The stronger a candidate you are for the hire, and the more real the hire, the more likely your call will be received if not gratefully, then at least courteously. You may get that important feedback you need to help assess where you are in the process. Unless invited, don’t follow-up more than once a week. An email can be another way to touch-base with the recruiter or hiring manager.
Stage: The degree to which you should follow-up is dependent on where you are in the hiring process. If you have had a 2nd interview or further, I think it is appropriate to check-in if they hiring company or recruiter doesn’t get back to you by the promised date. You can do so after a first interview if they have not gotten back to you. However, at the first interview stage, I wouldn’t follow-up by phone more than once unless encouraged to do so.
2nd+ Choice: In practice, a delay following a short-list interview often means that someone else was the first choice and is being made an offer and that they are waiting to see how that goes before getting back to you. In this case, you need to hang-in there to find out the result, or move on.
Changing Priorities: Unfortunately, the corporate world has its own agenda. Budget freezes. Acquisitions. Strategic discussions. Changing priorities. Even the holiday of a key decision maker might be the cause of a delay in the hiring process. If they have business reasons for the delay, there is nothing you can do about it.
In the end, you need to take your cues from your the recruiter, hiring manager or executive recruiter. If you are receiving encouraging feedback, follow-up. If you aren’t sure, ask. “Shall I follow-up in a week?” The response, and tone of response, will give you a sense of where you stand. If you don’t receive negative cues, but not an outright rejection, move on. You should always be exploring other options until you receive that final offer.