Tuesday 18 August 2015

Story Points: Another tool, Not a Hammer!

*bang head on desk*


*bangs head on desk again*

Nope. Still can't knock that alleged sense into me.

Today has been one of those days that started off OK, then I saw a conversation on twitter which got me all het-up (not necessarily in a bad way). It seems I'm returning yet again to the issue of story points and the #NoEstimates #BeyondEstimates movement. I've covered so many topics in this space it's getting frankly tedious to repeat myself. If you're interested in the kettle boiling, see:

What Ignited the Blue Touch Paper

I'm not all that bothered about story points. I use them a lot as they were intended. Relatively sizing tasks. I often also find myself using T-shirt sizing or occasionally Size, Complexity and Wooliness. They all have their merits depending on what the teams I work with decide they wish to use. The biggest problem is when I find some proponents of various methods, including of course Scrum, XP, RUP, Waterfall etc. trying to impose their way of thinking as the right way of thinking. We're just as guilty of this in the agile world as the 'waterfall' managers we often criticise.

Truth be told, with estimates, I don't care a jot which we use. If you believe every situation is different, then you should expect that the tools used may well be different and that's OK.

The problem we have is that many folk are critical of story points as they are used as a stick to beat developers with. If you've ever worked in business or perhaps even running a charity, then you'd know that this is only one of many possible outcomes of why estimates are important. It's just that developers seem to take offence to the idea more than most. Also, bear in mind the maturity of a team creates or negates the need for precise estimates. Indeed, if a DevOps team is mature enough to delivery through MVP (lean-thinking/startup) then adhering to 'hard' estimates is much less important as the outcome of a miss is simply the value in the missed version of the software, not value overall, since the client already has something they can work with. However, I digress...

Story Points to Reality: Parametric Equations

Many proponents standing against story points seem to fail to realise that a story point link to the real world exists whether we like it or not. A story takes time to do. You don't have negative time and you can't carry out zero duration tasks. It also doesn't cost zero, because the developers wages or rates are being paid (yes, you ar coting the business money - Sorry but it's true. Even if you work for free and are late you lose the company an opportunity cost). That is just as much a reality as the law of gravity. Just like gravity, your mind has to escape to outer space to escape that reality. The value a story delivers can also be quantified and analysed statistically. All of these re-quantifications have units of measure which can legitimately be attached to the parameter.

To recap, in A-level maths (senior high for those in the US and a heck of a lot younger in many other countries), most people should have come across the concept of a parametric equation. It usually includes a variable which itself has no units to simplify the process of reasoning about the model at hand. Consequently, it allows for much easier expression of much more complex structures and concepts in easier to use form. In a tenuous way, it's akin to the mathematical equivalent of using terms such as SOLID, IoC, TDD, BDD etc. since just using these words helps communicate ideas where communication is the goal. Just like in the software world, there is often a transformation in and out of the real world context of parametric equations (read, parameters). This is a normal, analytical approach to many problems in many more industries than software development or engineering. The only difference between these is that parametric equations contain a stochastic component when working with flow of tasks across a board. That doesn't often change the approach needed, just the skill of the person using them (which may or may not be desirable). But guess what? So do story points.

Crucially, and this is the bit that gets me wound up, just because people choose to play with the numbers incorrectly, which many project managers, scrum masters and product owners do, doesn't invalidate the analytical position, nor does it invalidate the statistics around these numbers. It also winds me up because it is very often the same folk who have made these statements that never followed process when more formal methods of software development were used. They just want to code. Lots of great noises, but when it's time to walk the walk...


Story point are just a tool. A tool like any other. If you misuse a tool, who is at fault?

Now #NoEstimates  #BeyondEstimates. I'd love for us to drop the NoEstimates term. It's got the dev world in the space of the top of the Gartner hype curve for absolutely no reason. #BeyondEstimates is a much better term for selling it, sure, but it also communicates the intent much much better. It's a term Woody Zuill came up with himself, which I think perfectly positions and communicates the goal of the movement. NoEstimates isn't about not estimating. It's about always looking to improve on estimates. So '#NoEstimates' is one of the worst phrases you can use to describe it. Plus, just like any tool, I suspect it's misuse will leave you in no better position than the standard evolving estimation processes, just with less understanding of where it all went wrong.

That said, overly precise estimates will leave you in worse positions than you'd otherwise be in. Get good at deciding how much effort needs to go into estimating things.

All Forecasts are Wrong

Yes, but what do you mean by 'wrong'? Wrong as in you'll never hit it? Yes. However, what's an acceptable deviation?

For example, do you get out and measure your parking space at work before then renting a fork lift truck to lift your car and spending 8 hours positioning it perfectly in the space with millimeter precision, only to have to get into it at the end of that day to go straight home? No, I suspect not. You estimate the position of the car in the space, sample the space to make sure you can get out or are in the spot and there we go. Job done. 15 seconds.

The amount of waste is the amount of unusable extra space around your car and even that definition depends on who you are. Statistically, most people are likely get into that space on their first try. Second and third try includes almost everyone. However, nobody attempts to just crash their car into that spot. That is good enough. Is it 'wrong' if measured by the deviation from the very center of the space? It certainly is! Is it good enough for the job? Yes it certainly is.

Is this your #NoEstimates approach?
In reality, the #BeyondEstimates movement is right to ask the question of the role of estimation in software development projects and beyond (pun intended). What I don't want to see though is people blame estimation methods or worse, maths, for the failings of people. That was agile c2000+ when most folk adopted the wrong ideas around agility and I can't stand to see another 10 years lost to needless bad practice.

This all means that teams have to get better at managing variation. Product owners have to get better at managing their own 'expectation' around that variation and both have to keep track of the scope of their deliverables and how likely they are hitting the commitments they make. Overall the culture has to support pivots, backtracking and encourage the raising of issues and also the organisation must be able to support changes of direction. This is a much bigger problem than either 'party' can solve alone.



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