The seven-point scale is referred to in the  Implementation section for this credit in the LEED Reference Guide, and LEEDuser has heard that a requirement for such a scale has been consistently called for by reviewers.

Our understanding is that LEED is following the Likert 7-point scale as a standard. It is the most widely used and accepted approach to scaling questions in survey research. Likert scales can be 5-point but there is some debate in the survey world about 7-point being better.