Sunday, 7 June 2009

Myth Busted - NOT

In a recent post Scott Ambler starts by claiming

Agile Myth:High Quality Costs Less than Low Quality - Busted! (at scale)

later on when reading the actual content Ive learnt that he refers to very specific cases :

For example, in situations where the regulatory compliance
scaling factor is applicable, particularly regulations around protecting human life (i.e. the FDA's CFR 21 Part 11), you find that some of the URPS requirements require a greater investment in quality which can increase overall development cost and time.


This is particularly true when you need to start meeting 4-nines requirements (i.e. the system needs to be available 99.99% of the time) let alone 5-nines requirements or more. The cost of thorough testing and inspection can rise substantially in these sorts of situations.

In my opinion he went a little off charts with his claim.

First is the exact "Myth" so to speak? Is it a simple "High quality cost less"?

Well actually its a little more subtle than that. What the agile community has found once and again (as Scott mentions) is that it cost less to work in high quality mode, when you need to reach and sustain acceptable quality. After all quality is infectious. In general it cost less to produce crappy systems, but mostly those just fails when quality needs catch up.

But back to the examples.

I don't have experience with life critical systems. However, is there a possibility that what actually cost are the regulations themselves and not the underlying quality? Is there a way to reach the necessary life safety quality without following those costly regulations (at lower costs)? I don't know, I do know is that the FDA regulations are costly to implement and originate in a time before the Agile paradigm shift.

High Available (HA) system, on the other hand, I do understand. In fact I was in charge of developing a HA solution for a big billing company. And here Scott argument falls short.

Reaching 4 and especially 5-nines has nothing to do with the quality of the developed system. In order to get to that level of availability you must have an integrated solution and there lies the cost of 5nine systems.

So what myth has been busted?

Yes there are cases in which a specific aspects of quality will drive costs up. But taking a very specific examples and generalizing it to "Busted (at scale)" that an obvious Mistake in my book.


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