Why are some duplicate individuals highlighted yellow?

Why are some duplicate individuals highlighted yellow?

In addition to a standard comparison against the full name, RecruitTrack™ also does a comparison on the first initial, last initial only.  These comparisons are highlighted in yellow.  The purpose of this first initial, last name comparison is to eliminate duplicates caused by variations of the first name.  For example, Dave Smith and David Smith would be shown as potential matches in the first initial, last initial comparison.