If tenants don’t participate in tracking, you can extrapolate purchasing data from other tenants to estimate purchase quantities. However, all of those estimated purchases are assumed to be noncompliant for the purposes of LEED. That raises the percentage of purchases by participating tenants that must be compliant. (See example calculation in the Documentation Toolkit.) You can, however, exclude product tracking for up to 10% of the total building floor area, and not be penalized in this way. You will treat the excluded purchases as if they do not exist—you won’t have to treat them as if they are non-compliant.