i was at the same event this weekend, and i think the real issue at hand is that none of us knows what HBS (or any top tier school is looking for). on the one hand, youve got a plethora of I-bankers, consultants, etc. etc. with great resumes, great pedigree, pretty heavy community involvement and pretty good gmats who won't get interviewed (HBS only interviews about 20% of their applicants).
on the other hand youve got people like me with no pedigree, pretty simple (relatively speaking) work experience, and decent GMAT who get invites.
there's no real formula for guessing who is in contention. i think most of it comes down to your essays and how you come across in your entire app. using this definition, i'd say that most, if not all potential applicants, are 'in contention' to begin with
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