Your online application will go through several stages:

Application Submitted/Received

We have received all required application components and have begun to review your application. During this stage, your application is reviewed by at least two admissions officers, after which you'll be either invited to interview or denied admission. Please note that August-entry Regular Decision applications will not be reviewed earlier than December 1.

For all terms of entry, our goal is either to invite applicants for an interview or deny admission within six weeks of a completed application being received. Our goal for interviewed applicants is to render a final decision within two weeks of the interview report being completed.

Keep in mind applications cannot be reviewed until they are complete. Missing required materials, updated test scores, or additional materials must be received by the Admissions Office within three weeks of your application submission.

Invited to Interview*

If you are invited to interview, you will receive an e-mail with instructions on how to set the interview up. Interviews are usually conducted by alumni in or near your hometown. If one is not available, you will be invited to interview via telephone or Skype either with an admissions officer or with a current student. Please be aware that your interviewer will not be familiar with the details of your application except your professional résumé, if you choose to provide one. The timing of an interview invitation has no bearing on the likelihood of your acceptance to Columbia Business School. Interviews are by invitation only; they cannot be requested by applicants.

Complete*

Within a week following the interview, your interviewer should submit a report to the Admissions Office. Once the report is received, you will receive confirmation by e-mail and on your applicant status page.

Final Decision Is Rendered

A final decision of either Admission, Wait List, or Denial can be rendered at any time. Our goal is that interviewed applicants will receive a decision within two weeks of a completed interview report. All decisions are final.

Source: www8.gsb.columbia.edu