cumulativehypotheses

That is, in the technical, sense used in Lean manufacturing, who’s first two principles include:

1. Specify value from the standpoint of the end customer by product family.
2. Identify all the steps in the value stream for each product family, eliminating whenever possible those steps that do not create value.

The “steps that do not create value” are waste. If our product is, or contains a lot of, software, is the action of testing that software waste, that is, not creating value from the standpoint of the end customer?

At the time of writing I am choosing the carpets tiles for our new office. On the back of the sample book is a list of 11 test results for the carpet relating to various ISO, EN and BS standards, eg the EN 986^* dimensional stability of these carpet tiles is < 0.2%—good to know! There are also the marks of cradletocradle certification, GUT registration, BREEAM registration, a few other exotica and a CE mark. Why would the manufacturer go to all this trouble? Partly, because of regulation: an office fitter would baulk at using carpet that did not meet certain mandatory standards. And partly because customers like to see a certain amount of testing.

Take a look around your home or office, I’ll bet you have a lot of small electrical items of various kinds. Low-voltage power supplies, in particular.  Take a look a them. You will find on some the mark of Underwriters Laboratories, which indicates that the manufacturer has voluntarily had the product tested by UL for safety, and maybe for other things. If you’re in the habit of taking things apart, or building things, you might also be familiar with the UL’s “recognised component” mark for parts of products. On British made goods^† you might see the venerable British Standards Institution “Kite Mark” , or maybe on Canadian gear the CSA mark , on German kit one of the TÜV marks, and so on. These certifications are for the most part voluntary. Manufacturers will not be sanctioned for not obtaining these marks for their products, nor will—other than in some quite specialised cases—anyone be sanctioned for buying a product which does not bear these marks.

Sometimes a manufacturer will obtain many marks for a product, and sometimes fewer, and sometimes none. I invite you to do a little survey of the electrical items in your office or home: how many marks does each one have. Do you notice a pattern?

I’ll bet that the more high-end a device—in the case of power supplies, the more high-end what they drive—the more marks the device will bear, and the more prestigious those marks will be. Cheaper gear will have fewer, less prestigious marks—ones that make you say “uh?!”^†† and the very cheapest will have none.

If testing is waste, why do manufacturers do this?

How does your answer translate to software development?

* BS EN 986:1995—Textile floor coverings. Tiles. Determination of dimensional changes due to the effects of varied water and heat conditions and distortion out of plane.

† tanks, missiles, land-mines, leg-irons, electric cattle-prods, that sort of thing.

†† There are persistent rumours that some Chinese manufacturers of questionable business ethics have concocted a mark of their own which looks from a distance like the mark