Lean Wastes & Tools

The IASSC Yellow Belt Body of Knowledge lists seven elements of waste. Which name does it use for the waste of making defects that must be reworked or scrapped?

• AConveyance
• BCorrection✓
• COverprocessing
• DMotion

Answer: IASSC's seven elements of waste are overproduction, correction, inventory, motion, overprocessing, conveyance and waiting. Correction is the waste of defects and the rework, scrap and re-inspection they cause; many other courses simply call it defects. Conveyance is IASSC's term for moving materials, and overprocessing is doing more than the customer requires.

In the IASSC list of seven elements of waste, what does 'Conveyance' mean?

• AUnnecessary movement of people, such as reaching and walking, within a work area
• BUnnecessary movement of materials or products between process steps or locations✓
• CIdle time while people or materials wait for the next process step to begin
• DDoing more work on the product than the customer requires or will pay for

Answer: Conveyance is IASSC's name for what many courses call transportation: moving materials or products between steps or locations when the move adds no value. Moving people within a work area is motion, idle time is waiting, and doing more than the customer needs is overprocessing.

A Pareto chart is most useful for:

• AIdentifying the 'vital few' causes that account for most of the problem✓
• BMapping the physical flow of materials and people through the factory floor layout
• CDisplaying the correlation between two continuous variables on a scatter plot
• DShowing how a process characteristic changes over time against upper and lower control limits

Answer: A Pareto chart ranks causes by frequency or impact, helping teams focus on the vital few that drive most of the problem (the 80/20 principle).