Woman thinking
06/05/2015 • Dorien Jorissen

The peril of experience assumption

In software development, assumptions can have a serious impact and we should always be on the look-out. In this blog post, we talk about how to deal with assumptions when developing software.

Imagine…you’ve been driving to a certain place


A place you have been driving to every day for the last 5 years, taking the same route, passing the same abandoned street, where you’ve never seen another car. Gradually you start feeling familiar with this route and you assume that as always you will be the only car on this road. But then at a given moment in time, a car pops up right in front of you… there had been a side street all this time, but you had never noticed it, or maybe forgot all about it. You hit the brakes and fortunately come to a stop just in time. Assumption nearly killed you.

Fortunately in our job, the assumptions we make are never as hazardous to our lives as the assumptions we make in traffic. Nevertheless, assumptions can have a serious impact and we should always be on the look-out.

Imagine… you create websites

Your latest client is looking for a new site for his retirement home because his current site is outdated and not that fancy. So you build a Fancy new website based on the assumption that Fancy means : modern design, social features, dynamic content. The site is not the success he had anticipated … strange … you have build exactly what your client wants. But did you build what the visitors of the site want? The average user is between 50 – 65 years old, looking for a new home for their mom and dad. They are not digital natives and may not feel at home surfing on a fancy, dynamic website filled with twitter feeds and social buttons. All they want is to have a good impression of the retirement home and to get reassurance of the fact that they will take good care of their parents.

The more experienced you’ll get, the harder you will have to watch out not to make assumptions and to double-check with your client AND the target audience.

Quote from Dalai Lama

Another well known peril of experience is “the curse of knowledge“. Although it sounds like the next Pirates of the Caribbean sequel, the curse of knowledge is a cognitive bias that overpowers almost everyone with expert knowledge in a specific sector. It means better-informed parties find it extremely difficult to think about problems from the perspective of lesser-informed parties. You might wonder why economists don’t always succeed in making the correct stock-exchange predictions. Everyone with some cash to spare can buy shares. You don’t need to be an expert or even understand about economics. And that’s the major reason why economists are often wrong. Because they have expert knowledge, they can’t see past this expertise and have trouble imagining how lesser informed people will react to changes in the market.

The same goes for IT. That’s why we always have to keep an eye out, we don’t stop putting ourselves in the shoes of our clients. Gaining insight in their experience and point of view is key in creating the perfect solution for the end user.

So how do we tackle assumptions …?

I would like to say “Simple” and give you a wonderful oneliner … but as usual … simple is never the correct answer.

To manage the urge to switch to auto-pilot and let the Curse of Knowledge kick in, we’ve developed a methodology based on several Agile principles which forces us to involve our end user in every phase of the project, starting when our clients are thinking about a project, but haven’t defined the solution yet. And ending … well actually never. The end user will gain new insights, working with your solution, which may lead to new improvements.

In the waterfall methodology at the start of a project an analysis is made upfront by a business analist. Sometimes the user is involved of this upfront analysis, but this is not always the case. Then a conclave of developers create something in solitude and after the white smoke … user acceptance testing (UAT) starts. It must be painful for them to realise after these tests that the product they carefully crafted isn’t the solution the users expected it to be. It’s too late to make vigorous changes without needing much more time and budget.

An Agile project methodology will take you a long way. By releasing testable versions every 2 to 3 weeks, users can gradually test functionality and give their feedback during development of the project. This approach will incorporate the user’s insights, gained throughout the project and will guarantee a better match between the needs of the user and the solution you create for their needs. Agile practitioners are advocating ‘continuous deployment’; a practice where newly developed features will be deployed immediately to a production environment instead of in batches every 2 to 3 weeks. This enables us to validate the system (and in essence its assumptions) in the wild, gain valuable feedback from real users, and run targeted experiments to validate which approach works best.

Combining our methodology with constant user involvement will make sure you eliminate the worst assumption in IT: we know how the employees do their job and what they need … the peril of experience!

Quote about Assumption

Do we always eliminate assumptions?

Let me make it a little more complicated:

Again… imagine: you’ve been going to the same supermarket for the last 10 years, it’s pretty safe to assume that the cereal is still in the same aisle, even on the same shelf as yesterday. If you would stop assuming where the cereal is … this means you would lose a huge amount of time, browsing through the whole store. Not just once, but over and over again.

The same goes for our job. If we would do our job without relying on our experience, we would not be able to make estimations about budget and time. Every estimation is based upon assumptions. The more experienced you are, the more accurate these assumptions will become. But do they lead to good and reliable estimations? Not necessarily…

Back to my driving metaphor … We take the same road to work every day. Based upon experience I can estimate it will take me 30 minutes to drive to work. But what if they’ve announced traffic jams on the radio and I haven’t heard the announcement… my estimation will not have been correct.

people holding cards with numbers 2 and 4

At ACA Group, we use a set of key practices while estimating. First of all, it is a team sport. We never make estimations on our own, and although estimating is serious business, we do it while playing a game: Planning poker. Let me enlighten you; planning poker is based upon the principle that we are better at estimating in group. So we read the story (chunk of functionality) out loud, everybody takes a card (which represent an indication of complexity) and puts them face down on the table. When everybody has chosen a card, they are all flipped at once. If there are different number shown, a discussion starts on the why and how. Assumptions, that form the basis for one’s estimate surface and are discussed and validated. Another estimation round follows, and the process continues till consensus is reached. The end result; a better estimate and a thorough understanding of the assumptions surrounding the estimate. These explicit assumptions are there to be validated by our stakeholders; a great first tool to validate our understanding of the scope.So do we always eliminate assumptions? Well, that would be almost impossible, but making assumptions explicit eliminates a lot of waste.

Want to know more about this Agile Estimation? Check out this book by Mike Cohn.

Hey! This is a contradiction… So what about these assumptions?

Should we try to avoid them? Or should we rely on them?

If you assume you know everything … you will never again experience astonishment. As Aristotle already said : “It was their wonder, astonishment, that first led men to philosophize”.

Well, a process that validates the assumptions made through well conducted experiments and rapid feedback has proven to yield great results. So in essence, managing your assumptions well, will produce wonderful things. Be aware though that the Curse of Knowledge is lurking around the corner waiting for an unguarded moment to take over.

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Dorien Jorissen