Competency-based assessment Describe 'best practice' competency-based assessment (CBA). To do this: [4 a) Explain what CBA is and describe how it works. b ) CBA is a form of criteria-referenced assessment. Explain the differences between criteria and norm-referenced assessments. CBA aims to be client-focussed. Describe one (1) example of how you may apply a client-focussed approach when planning, develop eveloping or conducting assessments in your workplace.