Controlled & Uncontrolled Variation (2)

In the office, there could be:

Controlled Uncontrolled

Photocopier working at around 30 copies per minute

Both outside lines on phone engaged

Staff arrive within 5 minutes of starting time

Tea trolley arrives at about 11am each day

Different paper: photocopier jams

Phone system goes down

Train strike

Tea lady breaks leg: no trolley