Organizations need to diagnose their current operation performance and identify the opportunities for improvement in order to stay competitive. Thorough literature review was conducted to identify common diagnostic approaches utilized by organizations to identify operation improvements. Three common approaches were identified: 1) Quality Audit; 2) BEF Assessment; 3) Project Selection for Lean and Six Sigma. Each of these approaches has it prowess and limitations. At the same time, each approach’s limitations can be complimented and improvised by other approaches’ prowess. This paper reviewed and discussed the available prior framework of operation diagnosis to identify the improvement opportunities that either utilised the quality audit, BEF assessment and lean sigma project selection. Finally the prior framework gaps and future focus are presented.