Agile Software Development Saves Lives!

Agile Software Development Saves LivesAhem. Actually that’s a bit of an exaggeration. I have to be honest with you. Agile software development probably doesn’t really save lives. There, you heard it from me first. I just felt like being melodramatic…

Someone once joked with me that “agile is great, but you wouldn’t use it
on an air traffic control system!”

Actually, I would.

In fact, I wouldn’t dare use anything else.

But agile is just a concept – a set of values and principles. What specific agile practices would be most appropriate in a life or death situation like this?

Those who read my blog will know I’m a big fan of Scrum. I have used Scrum on its own, without any other agile practices, and with a great deal of success. I would probably still use Scrum as the management approach to an air traffic control system, but I certainly wouldn’t use it on its own.

For a project like this, where quality is absolutely critical and lives depend on it, I would put a strong emphasis on XP (Extreme Programming).

Personally I would describe Scrum as an agile management method, whereas XP is more about agile engineering and XP has some important practices to assure quality.

One is Pair Programming. If we’re going to write code that people’s lives depend on, there’s no way I would want a single line of code written by any one person. I would want every line scrutinised, every assumption challenged, and every line sanity-checked with a second pair of eyes. With Pair Programming, this level of continuous peer review obviously comes as standard.

Another QA aspect of XP is automated unit testing and Test Driven Development (TDD). On a project like this, I would want 100% test coverage. I would want to know that every scenario had repeatable tests, so we could be completely sure that nothing ever regressed after passing the initial tests without us knowing about it. Anything less would simply be inadequate.

There are many specific practices in Scrum and XP that would help to mitigate risk and assure quality on a project as critical as an air traffic control system. But these two practices in particular – Pair Programming and Test Driven Development – if followed religiously, I am sure would deliver higher quality code than any other approach to development and testing.

In commercial situations, this level of rigour isn’t always appropriate or affordable. But when quality is paramount, these engineering practices make complete sense. For an air traffic control system, the overhead of doing them 100% of the time is completely justified by the lives they could save.

In a situation like this, I wouldn’t have it any other way.


Photo by Akinori YAMADA

4 Responses to “Agile Software Development Saves Lives!”

  1. wic says:

    I agree, but just wanted to point out that XP does in fact contain pretty much everything when it comes to planning, stories, retrospective etc. XP is more than just a handful of programming practices.

    I tend to be skeptical about teams who "only" uses Scrum. Things usually starts of well but after a while they amass lots of technical dept because scrum does not bother with the engineering practices. This is a problem with Scrum imo.

  2. Pawel Brodzinski says:

    Would you write unit tests for setters and getters in interfaces too? Otherwise you wouldn't have 100% coverage anyway.

    I'm just being curious. I actually don't believe much in value of having 100% code coverage. What works better for me is having developers who consciously decide whether to write a test or not and if their decision is positive what king of tests these should be.

    Key value of unit tests is brought by testing marginal conditions and standard 2+2 test covers the code exactly the same as several tests checking specific cases.

    This is by the way the reason why I don't expect to see 100% coverage.

  3. Stephen says:

    The whole premise of the title statement (or rather from its opposite) is misleading, and, IMO, stems from the general misconception about agility.

    The issue with developing mission/life-critical systems is not about agility but about quality. You correctly identify XP as possessing some practices that help ensure quality. The benefit of Scrum would be that flaws in critical components would (ideally) become manifest early, contributing to guiding the development process.

    Unfortunately, quality is something that is as easily overlooked in so-called agile projects as in more traditionally-modelled counterparts.

  4. MyOpenDraft says:

    Nice post ;) we should consider different factor when adopting agile in enterprise, i think the most effective way is to evaluating different agile practices and applying hybrid model in your organization.

    You should do what you need and ignore other practices if you think it's not effective for your situation.

    Just learn from mistake and apply process improvement technique.

Leave a Reply

What is 2 + 1 ?
Please leave these two fields as-is:
Please do this simple sum so I know you are human:)

There are 101 ways to approach anything.
To find the best way, sometimes you need expert help

What People Say

“Kelly revolutionised the way our digital department operated. A true advocate of agile principles, he quickly improved internal communication within our teams and our internal clients by aligning our business and creating a much enhanced sense of transparency in the decisions the business was making. Kelly also introduced a higher sense of empowerment to the development teams...”


“Kelly’s a leading program director with the ability to take charge from day one and keep strong momentum at both a program and project level driving prioritisation, resourcing and budgeting agendas. Kelly operates with an easy-going style and possesses a strong facilitation skill set. From my 5 months experience working with Kelly, I would recommend Kelly to program manage large scale, complex, cross company change programs both from a business and IT perspective.”


“Kelly is an extremely talented and visionary leader. As such he manages to inspire all around him to achieve their best. He is passionate about agile and has a wealth of experience to bring to bear in this area. If you're 'lucky' he might even tell you all about his agile blog. Above all this, Kelly is great fun to work with. He is always relaxed and never gets stressed - and trust me, he had plenty of opportunity here! If you get the chance to work with Kelly, don't pass it up.”


“Kelly is an Agile heavy-weight. He came in to assess my multi-million $ Agile development program which wasn’t delivering the right throughput. He interviewed most of the team and made some key recommendations that, when implemented, showed immediate results. I couldn’t ask for more than that except he’s a really nice guy as well.”


“Kelly and I worked together on a very large project trying to secure a new Insurer client. Kelly had fantastic commercial awareness as well as his technical expertise. Without him I would never had secured this client so I owe a lot to him. He is also a really great guy!”


“Kelly came to the department and has really made a huge impact on how the department communicates, collaborates and generally gets things done. We were already developing in an agile way, but Kelly has brought us even more into alignment with agile and scrum best practices, being eager to share information and willing to work with us to change our processes rather than dictate how things must be done. He is highly knowledgable about agile development (as his active blog proves) but his blog won't show what a friendly and knowledgeable guy he is. I highly recommend Kelly to anyone looking for a CTO or a seminar on agile/scrum practices - you won't be disappointed!”


“Kelly was a great colleague to work with - highly competent, trustworthy and generally a nice bloke.”


“Kelly was engaged as a Program Director on a complex business and technology transformation program for Suncorp Commercial Insurance. Kelly drew on his key capabilities and depth of experience to bring together disparate parties in a harmonised way, ensuring the initiate and concept phases of the program were understood and well formulated. Excellent outcome in a very short time frame. ”


“I worked with Kelly on many projects at IPC and I was always impressed with his approach to all of them, always ensuring the most commercially viable route was taken. He is great at managing relationships and it was always a pleasure working with him.”


“I worked with Kelly whilst at Thoughtworks and found him to be a most inspiring individual, his common-sense approach coupled with a deep understanding of Agile and business makes him an invaluable asset to any organisation. I can't recommend Kelly enough.”


“Kelly was a brilliant CTO and a great support to me in the time we worked together. I owe Kelly a great deal in terms of direction and how to get things done under sometimes difficult circumstances. Thanks Kelly.”