Monday was a public holiday in the UK. We had a typical British summer’s day – watery sunshine interspersed with periods of torrential rain. We needed to keep the kids occupied somewhere new and somewhere indoors, so we decided to visit Paradise Mill. Macclesfield used to be a leading centre for the manufacture of silk garments, and Paradise Mill is a fully restored working Victorian silk mill. The exhibits are great, and the tour is terrific – the kids got to try some of the work that their counterparts (they’re aged 8 and 6) would have been doing in the 1820s!
On the wall at one end of the main weaving room was a notice from the mill’s owners, entitled “Don’t pass on faults”. The mill workers were all paid according to the amount of work they did each week – for example the loom operators were paid a penny or two for each inch of completed, perfect silk cloth. The notice pointed out that any worker who did a faulty piece of work should fix it themselves, and not allow it to be found by the next worker in the process. Faulty work, the notice advised, slows down your co-workers (and so reduces their pay), slows you down (and so reduces your pay) and may create a bad impression on customers (resulting in loss of business and therefore less pay for everyone). The impact was stated just like that – baldly in financial terms.
I remembered reading that the same philosophy held in the 1920s in the Toyoda Spinning and Weaving works. But instead of writing a notice, the mill’s owner Toyoda Sakichi implemented a series of failsafe devices that automatically stopped the looms if they detected a fault. In this mill it was near impossible to pass on a fault. And this became one of the pillars of lean production – pursuit of perfect quality makes the whole process faster and more predictable.
As we know, test-driven development and the daily build help to do this for software development. A while back a very senior manager in a large multi-national dismissed my efforts to improve the agility of a group of software projects: “No defects at all? You’re living in a dreamland!” Paradise Mill, anyone?