Process improvement: Lean, Six Sigma and data

Lean: remove waste

Lean (from the Toyota Production System) focuses on delivering value with less waste. The 8 wastes (DOWNTIME):

• Defects: errors and rework.
• Overproduction: making more than needed.
• Waiting: idle time between steps.
• Non-utilised talent: not using people's ideas and skills.
• Transportation: unnecessary movement of materials.
• Inventory: excess stock.
• Motion: unnecessary movement of people.
• Extra processing: more work than the customer values.

Lean tools: value stream mapping, 5S, kanban (visual pull signals), poka-yoke (mistake-proofing: a connector that only fits one way), standard work, kaizen (continuous small improvements by the people doing the work), and Gemba walks (go and see the actual work).

Six Sigma: reduce variation

Six Sigma uses data to reduce defects and variation, following DMAIC:

1. Define the problem, customer impact and goal ("Reduce wrong-item deliveries from 2% to 0.5% in 3 months").
2. Measure the current performance with reliable data.
3. Analyse root causes: fishbone (Ishikawa) diagrams, 5 Whys, Pareto charts (80/20: a few causes create most defects).
4. Improve: test solutions (pilots), implement the best.
5. Control: SOPs, training, control charts and monitoring so gains stick.

5 Whys example: Orders shipped late. Why? Packing was delayed. Why? Pickers waited for stock. Why? Put-away from inbound was slow. Why? Receiving happens at peak picking time with the same staff. Why? Shift planning doesn't separate inbound and outbound. Fix: schedule inbound receiving in a separate early shift.

Excel for operations

Interviews for operations roles often include an Excel test: VLOOKUP/XLOOKUP, SUMIFS/COUNTIFS, pivot tables, conditional formatting, IF/IFS logic, date functions (NETWORKDAYS for SLAs), charts, and basic dashboards. Practise building a daily operations MIS: orders, on-time %, delays by reason, and trends.

ERP systems

ERP software (SAP, Oracle, Microsoft Dynamics, Zoho, Tally for small businesses) integrates procurement, inventory, production, sales and finance so everyone works from the same data. Knowing basic transactions (creating POs, GRNs, stock reports) is a plus.

Check yourself

• Name the 8 wastes and give an example of each in a restaurant kitchen.
• Run a 5 Whys on "customers wait 20 minutes at the hospital billing counter".
• Which Excel functions would you use to calculate the on-time delivery % by city?