Operations, Quality and Productivity Management
This domain tests whether you can design and control delivery processes, measure productivity honestly, and distinguish quality assurance from inspection.
Core rules and concepts
- Operations transform inputs (labour, materials, information) into outputs through a process; performance is judged on cost, quality, speed, dependability and flexibility.
- Scheduling tools include Gantt charts for communication and critical path method for logic. Float is the time an activity can slip without delaying completion; critical activities have zero float.
- Lean thinking attacks waste (waiting, overproduction, rework, transport, inventory, motion, over-processing) and pulls work at the bottleneck. A constraint is managed, not starved.
- Productivity = output divided by input. Partial measures use one input (labour hours per unit); total factor productivity uses all inputs. Output value must be measured consistently.
- Quality: fitness for purpose and conformance to requirements. Quality assurance covers the system that prevents defects; quality control covers inspection and testing that detects them.
- Cost of quality has prevention, appraisal, internal failure and external failure categories. External failure is the most expensive.
- TQM principles, PDCA, ISO 9001's process approach, Six Sigma's DMAIC, Kaizen and value engineering are the standard improvement frameworks.
Worked example
Month 1: 480 units with 1,200 labour hours, so 2.50 hours per unit. Month 2: 520 units with 1,400 hours, so 2.69 hours per unit. Output rose 8.3 per cent but labour input rose 16.7 per cent, so labour productivity fell by about 7 per cent (0.400 to 0.371 units per hour). Reporting only the output rise would hide the deterioration. The follow-up question is whether the extra hours were overtime on rework or genuine learning time on a new activity.
Traps that cost marks
Using output volume as a productivity measure; calling inspection quality assurance; classifying rework as a prevention cost; ignoring that critical path activities cannot be accelerated by adding float; and quoting unit rates without stating the input basis.