Not concise:

The admissions committee will read many personal statements, and they want to gain the information in as efficient a manner as possible.

Concise:

The admissions committee will read many personal statements, and they want to gain the information as efficiently as possible.

Comment:

You don’t need to write “as efficient a manner,” because we know that “efficient” is a “manner” or “style.” This is like saying “She is trustworthy in character.” Instead, you can write “She is trustworthy,” because readers know that is a comment on her character.