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The unwinding of complexity

O desenrolar da complexidade

Every object, website or app, every service or process – every toaster, dermatology appointment at the Coimbra Hospital or online purchase of health insurance – is associated with an unyielding amount of complexity.

This complexity cannot be reduced nor eliminated. Oftentimes, however, it can migrate from the user, customer or citizen to the system – to the company and its programmers, store managers and support lines.

As designers, engineers and directors, seeing this complexity where others see the ordinary allows us to simplify the “things” that we help to conceive and implement, where others stop, already happy with the result. It allows us to create truly invisible or easily distinctive experiences.


On lonely nights, I devour physics presentations, full of stories about how the universe works. There are many of these stories and, when they are good ones, they are called theories. And when the theories are good, they are called laws. Of all of the laws that describe the world, there is one type known as “laws of conservation”. Among them is the most famous:

“In nature, nothing is created, nothing is lost, everything is transformed.”
– The Law of Conservation of Energy, in the words of Lavoisier.

As in physics, in people-centred design there exists an identical law as well: the Law of Conservation of Complexity.

Examining products, services and processes through the eyes of this law has helped me, over the years, to find problems, sketch out ideas and discuss solutions with the teams of projects I have worked on.


Complexity can be found everywhere: in the bathroom faucet of a hotel, in the forms for opening and closing business with the tax authority, and in the forest fire coordination and response protocol.

  • It is as present in a one-page-layout website – dynamic, clean and with modern lines – as it is in the unsightly MS-DOS app for recording appointments at the Mortágua Health Centre.
  • It affects my aunt Graça, a sexagenarian with a fourth-grade education from the obscure village of Vale de Mouro, and bothers the young, cosmopolitan and tech savvy Dr. Sebastião Fonseca.

In the multitasking of our everyday hustle and bustle, even something as trivial as going through a door can become a complex activity…
(caption: Inevitably arduous, complexity is oftentimes
merely annoying, while other times painful.)

All joking aside, complex situations can:


It is the year 1983. These days, Larry Tesler is an interaction designer at Apple, and tries to convince the management to implement his ideas.

To do so, Larry postulates that, just like with energy, there is an inherent amount of complexity in every object, Internet page or computer app, in every service or process – in teapots, MB WAY transfers and visits to Loja do Cidadão – an amount that is unyielding and that, just like the energy of Lavoisier, does not disappear, but can only change place.

To make his theory more credible and persuasive, Larry packages it under the astute name of: Law of Conservation of Complexity.


OK, so things have their own unyielding amount of complexity… obviously! Turning to Tesler’s Law, we can even justify and underestimate the difficulties experienced by people who interact with our products:

“Of course, that’s just how it is, [insurance] is a complex thing!”

We can replace [insurance] with many other terms: home mortgage, submission of Personal Income Tax Form 3, letters from Social Security, software for recording nursing acts, cable TV bills.

“And some things are not so complex; some people are like… wimpy. They don’t pay attention while doing things. Some people don’t even read the user manual! With that mindset, of course everything is complicated. And at first this is also normal… once you learn, it’s even easy.”

Does this all sound familiar?


Now seriously: if complexity that cannot be avoided exists, then the question to be asked, just like Larry at the time, is who will have to deal with this complexity? The end user – customer, user, citizen – or the development and design team, marketing team, product and sales team?

For the success of my business, whose time is more valuable? Two additional days of a designer simplifying an interaction + one extra week of a programmer adding intelligence to a code + a powerful new server… or three more minutes of time per day for one million customers?

  • Will it be more profitable to replace abbreviations and codes, banking jargon and names that are cut off or without accents on accounting statements instead of having the bank support line inundated with trivial questions? Those who have never spent a few minutes deciphering bank statements can cast the first stone.

Is it better to spend time writing a Social Security letter in clear language, with specific and personalised instructions and data, or to have the recipients of these letters, in the subsequent days, standing in line at Loja do Cidadão to find out what to do with the notice they received in the mail?


In addition to the already mentioned swollen noses, tax liens and nuclear panic, losing existing or potential customers is another consequence of complexity: in the case, for example, of an online shoe store, our online competition is just one tab away, making the words of Jakob Nielsen my own. Food for thought…

As a paradox to what might be expected, in the case of an app – or any other product or service – the cheaper it is, the less complex it must be. It is as if a Renault Clio would be easier to use than an A-Class Mercedes.

Consequently, something free has to be very easy to use, or it runs the risk of being switched out at any time. The only thing that secures the user to a website or app is their “reservoir of goodwill”, and complexity is halfway down the path to quickly draining it:

Caption: After this experience at Midas, if at Norauto they show Andreia a quote,
without asking for personal data, location, nor questions in French,
what will be the likelihood of her asking Midas to do her servicing?

The above experience with Midas causes a re-assessment of the idea floating around in many heads that there is nothing that people love more than to spend their free time filling out forms, logins and records, and providing personal data for “marketing purposes”. For those who like numerical arguments, there is the story of the $300 million button.

In the eyes of Tesler…

  • We should not view a change in the user’s sophistication for the system as a cost, but rather as an investment, like a customer retention magnet.
  • Removing difficulty from critical aspects of the interface (whether an app for border control, an SMS or a ticket dispenser at the pharmacy) is a synonym for sales, and an antonym for customer service calls.
  • Moving complexity distinguishes our services from the competition, providing experiences that are both memorable and imperceptible.


To wrap up the argument and, turning again to the ideas of Larry, in this era of commercial interfaces, computers and intelligent watches, cars and washing machines, SMSs and reams of A4 paper are no longer tailor-made. They are no longer completely unaffordable and do not run at a snail’s pace – even though, every now and again, I question whether my mobile phone actually has “more processing power than the computers that took man to the moon”.

Software may be more complex now, since it is designed and programmed only once and used daily by thousands of people.

For example, we can estimate the costs of the complexity of the National Health Service’s SClínico program, used daily by physicians throughout Portugal.

Who hasn’t already experienced one of these episodes in person?

Let us imagine then that, on average:

  1. The Portuguese Order of Physicians receives one complaint per week involving the complexity experienced with the system. A physician spends 10 minutes making the complaint, and the Order of Physicians spends 20 minutes reading and processing it.
  2. A physician encounters one problem of system complexity per appointment. This costs the physician one extra minute. A physician has 10 appointments per day, from Monday to Friday. There are 600 physicians in the country who also encounter the same situation.
  3. The support line receives one call per day to help one physician with one question of system complexity. The call lasts 10 minutes.
  4. The hourly cost of a physician is €30 (€0.5/minute), while for a support line technician it is €6 (€0.1/minute) and for an employee of the Order of Physicians is €12 (€0.2/minute).

As such, the annual cost for complexity is €728,658.00. More than €3.5 million in just five years!

If we keep going, estimating the costs associated with the problems of system soundness, slowness, downtime and lost user days as well, this amount quickly rises to alarming levels.

Furthermore, SClínico is just one type of software used by physicians during their workday. In addition, in a hospital, physicians are not the only healthcare professionals who interact with problematic software. And this does not even consider externalities such as:

  • decreased motivation, a breakdown in the mindset of physicians and the higher likelihood of unintentional mistakes;
  • the stress caused to support line technicians, when physicians unload their frustrations on them;
  • the perception of incompetence felt by users.  

Going back to the core question: is it worthwhile or not for the development team to spend time removing complexity from the system?

“Unless you have a sustainable monopoly position, the customer’s time has to be more important to you than your own.”
– Larry Tesler


OK, we are all on board:

  1. We aren’t dumb; it’s the things that are complex.
  2. Some of this complexity can be moved to make these things easier.

Let us consider then, as a case study, this beautiful and deceivingly simple, but quite complex, Alfa Romeo:

Using Tesler’s Law, where is the complexity?

  • Coordinating hands and feet to change gears is very complex (try to remember your first driving lessons).
  • Controlling the speed of the windshield wipers on a rainy night, while switching gears on the twists and turns of the Bussaco motorway, with our baby crying in the back seat, is even more complex.

And if the car were to take on this complexity? The driver could focus on the road – and the baby – and the car on the gears and the windshield wipers.

Similarly, in home banking:

  • António can simply indicate that he wants to send €200 to Maria, and the system has to figure out whether this entails an intra-bank, domestic, international, SEPA, SWIFT or Target 2 transfer.
  • Why does Joana have to get out her mobile phone, unlock it, navigate to the bank app, watch the logo animation for the thousandth time while the app opens, enter her PIN, go to her transactions and swipe through the list to see if she has received her salary? The system can take on this complexity by giving the good news to Joana, via SMS, when the transfer is received at the bank (a wage transfer has a specific code allowing the bank to distinguish it from others).

Form 3 for online income tax declaration, a plethora of complexity.
What is the difference between annex A, B, H or annex orange, pear and banana?
Between table 2, 3 and 4 or table bread, wine and pork rinds?

Taxes! Come on, let’s think big:

  • And if… “Taxpayer A” can simply itemise and confirm income and expenses from the previous year, and it is the system’s job to determine whether they go to annex A or H, whether they go to table 2 or 5, if it is better for them to be taxed through category A or B, whether it is preferable to do so separately or jointly with his beloved “Taxpayer B”?
  • And what if Social Security communicates with the Tax Office so that Alexandra does not have to fill out Annex SS of Form 3 every year, nor the brand-new and compelling Quarterly Return for workers with self-employment receipts?

It’s not only the big things – how to make an online purchase without having to register – it is also important to remove complexity from small, mundane things. Small everyday annoyances (just like losses by Benfica, at the Luz Stadium, with that god-awful Tondela) keep piling up and we realise it at home, at night, tired and irritated, without exactly knowing why.

Small details can have a major impact: showing the name of the account holder at the time we are making a transfer not only allows us to do the transaction faster, since we do not have to confirm and reconfirm the digits of the IBAN, but it also gives us much more confidence that our money will not be going to the wrong account.

Moving complexity stems from…

Persistently questioning the “why” behind things:

  • Why does the user really have to provide this information?
  • Doesn’t the company already have this information somewhere?
  • Can’t we ask this later?
  • Can’t the system deduce or infer this?  
  • Can’t we be a bit more specific in this point?

Asking jointly with our institution’s IT specialists and legal experts, teams in the field and the marketing department. Interaction design is a team sport.


Relaying complexity to the system is not always obvious, easy or cheap. However, it is not the only way to simplify things. The Law of Conservation of Complexity is not a law that cannot be broken like the laws of physics; it is merely a useful lens for us to see interfaces.

There are three ways of removing sophistication from the inventions that we, like little monkeys, have been configuring since the early days of mankind – from a kitchen window to the website of the restaurant of Mr. Inácio or the national competitive examination for the placement of hired teachers. They are:


As a specialist in usability, making things easier to learn and more user-friendly – i.e., making them more familiar – is something that lies close to my heart. However, without overextending myself, and going back to our case study of the Alfa Romeo, this could entail, for example: studying what would be the best organisation, the best location, the best type of handles, and the best symbols and terminology for the air-conditioning system.

For the website of Zara or the app for monitoring MOBI.E electric charging stations, boosting usability could involve:

  • adjusting the main navigation to most frequent tasks;
  • improving the clarity and relevance of texts;
  • streamlining search results.

Although the impact is not always highly visible, or enough to provoke a “wow”, enhancing the usability of our products and services must never be overlooked. No one has a good experience in a house where the plumbing does not work.

Test, test and test again…

The best way to have more user-friendly bicycles, health centres and photography apps is to test them with people (a topic for further examination in a future article). With real users. Test as soon as possible, test drafts and prototypes, test the competition and the product we already have on the market. Test, refine, test again, refine again… Will regular usability tests be performed on SClínico with physicians of various specialisations and with different technology skills?


Eliminating capabilities from existing products and services, or deliberately not including certain options in new projects, is another (possibly controversial) way that we can simplify things. One famous example is Google Docs: a deliberately reduced version of Microsoft Office.

“So much complexity in software comes from trying to make one thing do two things.”
– Ryan Singer, Product Strategy at Basecamp

The initiative’s success lies in properly choosing what to leave in and what to leave out, focusing on a narrower target audience. Every feature we add to our product increases the complexity of our design. Making our product more complete, with the aim of improving it, can have the opposite effect and downgrade the user experience.

Going back to our beautiful Italian car for the last time, what could we remove to make it less complex?

  • If data suggests that this car is primarily used by single men, we can consider removing the entire door locking panel and window control system next to the driver.
  • Let us imagine that 95% of people use the car in the mode in which they receive it. Perhaps, in the next version, we will have no buttons to connect to sports mode or to deactivate ESP on the dashboard.
  • Will most people really miss being able to adjust the low beams and the light intensity of the instrument panel?
To help us remember the design pains that come from lining up
feature after feature in products, at
we have the following bumper sticker clearly displayed: “More choices, more trouble.”

And again, for the last time, going back to the world of software, websites and apps, removing features may involve identifying:

  • pages that are not viewed;
  • definitions that are infrequently used;
  • products that are infrequently purchased.

Features and content often exist only because someone important has “asked” for them, such as the always important company organisational chart or the dynamic and compelling pre-login tour with animated GIFs.

Users flee from app presentations
almost as quickly as from the terms of use screen.

We should also question features to be built only because they reflect the habits and desires of the people involved in the project – managers, directors, programmers, financiers and marketers – all highly logical, proactive and persistent technology fans. Extreme users whose habits and needs are diametrically opposed to the actual people who use (or will use) the product or service.

  • Does the average user really want to use an advanced filter, sort a table by descending name and group items by type? Probably not.
  • Does a typical customer really have four credit cards and three debit cards, make dozens of purchases per day, with the habit of confirming the success of each transaction and patiently waiting for proof via PDF on their mobile phone? Hmmmmm…

Removing features thoughtfully

While discussing ideas between multiple people at the company is essential to move complexity, and performing regular tests with users is essential to improve usability, in order to remove or leave out features, it is critical to have data on: the users who we want to reach, and those that we will intentionally leave out;the tasks that they frequently perform and the information they most commonly search for, their basic needs and what they consider indifferent. This is achieved by combining multiple research methods, from contextual interviews and analytics to field studies and Kano analyses.


If you are a teacher, nurse, crane operator or judo instructor, you may be thinking, right now, something along the lines of:

“Wow, I had no idea that complicated things could be simpler! But I am just the end user, the customer, the one who uses it. Can I do anything to help?”

Yes, you can. You have two tasks just as important as my own and those of the project team:

  1. Give an Archie slap to anyone who answers: “Oh, so this is so easy, don’t you remember? You just go here, and then there, and do this, and then that… and that’s it!”
  2. Complaints. Express your difficulties and frustrations in an assertive manner with a given website or app, with a letter, with an announcement or a notice, with a store door, with signage (or the lack thereof), or with any other service or process.  

Don’t feel dumb if you cannot file your tax return alone, if you get lost in the hospital or if you forget that you had to take your “new” car, now five years old, to its first periodic inspection.

While dining at a restaurant, if you notice that your knife is dirty and dull, do you think to yourself: “How dumb of me! I just have to clean it with a cloth and push harder to cut the steak.” No. Most likely, you talk to the waiter and politely ask for a clean, sharp fork: the problem is not you, it’s the fork.

  • Do the same thing for 120-page health insurance contracts in size 8 font, filled with medical terms and legal jargon.
  • Do the same for the confusing way of scheduling meeting rooms on the intranet of the company you work at.
  • Do the same when you don’t understand why you have a transaction for €2.58 on your monthly account statement.

Complain in person or, preferably, in writing. As the old saying goes: “Spoken words fly away, written words remain.” Send your complaint via email to several different entities. Leave reviews at app stores. Your voice will make a difference, because:

  • It inconveniences and annoys important people, who do not want to be bothered with details, motivating them to insist that their employees fix the problems.
  • Your specific problem will eventually come to people like me, giving us not only important clues for us to make better designs, but also arguments to prioritise their correction.

I would like to give my personal thanks to all those who have spent a bit of their time complaining after experiencing difficulties with the products and services they come across in their daily routine.

I would recommend an article published previously in our blog about complaints, that might help you do them well.

NOTE: I am not saying that the SISone4ALL complex, for the control of wanted persons and assets in the European Union, should be as easy as using a simple kitchen knife. I am only saying that both can have unnecessary complexity. And that there will be certainly more in the case of the former compared to the latter :P.


  • Everything we create in our work and use in our day-to-day routine – a hand blender, a decree law, an air traffic control system – has an inherent and unyielding amount of complexity.
  • In the commercial era, where software is programmed once and used regularly by thousands of people, who must bear this complexity? The user or the system, the customer or the company, the citizen or the government? Whose time is more valuable for the success of the business?
  • Moving complexity does not exclusively entail structural improvements, such as the ability to log in to any government website using a mobile phone. Small details such as: “Alarm scheduled for eight hours, 23 minutes from now.”, rather than: “Alarm saved successfully”, also have a relevant impact on people’s lives.
  • We should look to the Law of Conservation of Complexity to promote change, educating teams and stakeholders that things do not have to be “just this way”. Changing complexity involves teamwork.
  • There are more ways to make an object, service or process less complicated: making it more user-friendly through tests with actual users, and leaving out or removing features based on research.

FINAL CAVEAT: Ideally speaking, we would research and discuss and test rampantly, and we would spend months or years on end to implement our beautiful, simple and unique experiences.

But moving complexity – to an app or to some poor sap on the basement floor of our contact centre, as well as improving usability – by providing more specific feedback and more intelligent forms, inevitably entails monumental efforts for development teams.

These efforts should not be undervalued. Keeping an eye on all of this complexity makes teams slower, less motivated and less efficient. We must compromise and reach a balance to unwind the complexity of our lives.

More on this topic in an article by Julien Zmiro:

The hidden cost of design complexity.