If your managers need to complete annual performance review forms, then the least you can do is make the ritual less menacing by shortening the form and eliminating redundancy.
The 9-Box is a commonly used tool to measure PERFORMANCE & POTENTIAL. If you're wondering about the difference between the 4 and 9-box read on:
The 9-Box measures PERFORMANCE and POTENTIAL
The 4-Box (The Employee Performance Continuum) measures just PERFORMANCE.
Performance is broken into two components: WORK RESULTS & BEHAVIOR.
Ask yourself what you are trying to achieve. If your goal is understanding and measuring employee performance then use the Employee Performance Continuum.
Try Using the Employee Performance Continuum to Measure Employee Performance