Why have you had so many jobs?

First, before you even get to the interview stage, you should try to minimize your image as job hopper. If there are several entries on your resume of less than one year, consider eliminating the less important ones. Perhaps you can specify the time you spent at previous positions in rounded years not in months and years.

Example: Instead of showing three positions this way:

06/1982 – 03/1983, Position A;
04/1983 – 12/1983, Position B;
01/1984 – 08/1987, Position C; …

it would be better to show simply:

1982 – 1983, Position A;
1984 – 1987 Position C...

In other words, you would drop Position B altogether. Notice what a difference this makes in reducing your image as a job hopper. Once in front of the interviewer and this question comes up, you must try to reassure him. Describe each position as part of an overall pattern of growth and career destination.

Be careful not to blame other people for your frequent changes. But you can and should attribute certain changes to conditions beyond your control.

Example: Thanks to an upcoming merger, you wanted to avoid an ensuing bloodbath, so you made a good, upward career move before your department came under the axe of the new owners.

If possible, also show that your job changes were more frequent in your younger days, while you were establishing yourself, rounding out your skills and looking for the right career path. At this stage in your career, you’re certainly much more interested in the best long-term opportunity.

You might also cite the job(s) where you stayed the longest and describe that this type of situation is what you’re looking for now.