Why a Multi-Rater Tool? Why not just have a supervisor assess an employee's leadership skills? Multi-rater (270° / 360°) assessments are generally considered more powerful than single source assessment tools. Multirater tool feedback is usually more accurate and more balanced than assessments restricted to the perception of an immediate supervisor. Additionally, a multi-rater instrument combines the input of a variety of sources and helps compensate for rater biases inherent in more traditional, single-source assessment instruments.