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Functionality and Usability

Every design solution has to prove itself on a daily basis.

The Question of If and How

There is a difference between “doing the right things” and “doing things right.” Creating well-functioning and easy–to-handle products is, of course, one of the responsibilities of industrial design. At the same time, a new concept should not only be effective but also efficient.


It works well.
What distinguishes a product that satisfies users? It has to function without any problems. If it can achieve this one thing it is already a useful product. This might sound self-evident but is far less common than one might think.

This aspect clarifies whether a thing actually works or not. In product design something is functional if it fulfills a certain task as it should. A hairdryer is functional if it dries hair, as is a bicycle that can be ridden and a razor that gets rid of the stubble on a man’s chin. The question of how well an object fulfills its task is a question of usability: its suitability for use.


The degree of usefulness.
The German standard: DIN EN ISO 9241-11 is not really a user-friendly definition and yet it defines product usability. It is present on products and software found to be: Effective, efficient and satisfactory. As user-satisfaction results from efficiency, effectiveness and a few other factors we can immediately delete the word ‘satisfactory’ from our memories and replace it with ‘practicability.’ But more on that llater, first we are going to have a quick look at two aspects: Effectiveness and efficiency.


Something is effective whenever the desired target is reached. For example, finding a parking space in the centre of London is quite effective no matter how long it takes. But if the search has lasted for hours and wasted gallons of gas that would not be very efficient at all. For gaining effectiveness in comparison to efficiency only the result counts - but not the effort it took. To be able to evaluate effectiveness from a design perspective one has to be a little bit more careful. A lack of effectiveness is not always the result of bad design. Take for example a razor: If it does not work properly the cause might not be bad design but could also be a technical issue or construction related.


Efficiency is the golden calf everyone dances around. And not without reason – it is the relation between effort and result. The question is: What is necessary to achieve a certain goal, how economical is it and will it pay off? The less the input and effort, the more efficient the result.

Effort means various things. Essential factors are the time, the energy and the concentration needed to be invested in achieving the goal. An outstandingly clear industrial design, for example, can reduce the time and concentration necessary for handling a tool and thereby improve its efficiency.


What characteristics does a mobile phone need to make it valuable? It needs to fit into a pocket and should not be too big or cumbersome. And what about a mobile storage device? It needs to be protected against potential damage from being dropped or falling out of a bag. These are things that could be categorized under practicability. This is a criterion even harder to grasp than efficiency and effectiveness because what is perceived as practical is, often enough, an individual decision and can be subjective. In general it can be said: Practicability means suitability for daily use. This can include aspects like compactness, stackability or transportability which makes us perceive of something as practical. Other points on the positive scale are high reliability and useful additional functions. Extravagant design can often sacrifice practicability for effect. What is the use of an elaborately designed product if it is far too bulky or easy to break? The design has rendered the product impractical.

Outdoor water taps installed in gardens or open spaces leave themselves vulnerable to the threat of being turned on an unauthorized third person who might cause flooding or water damage. Locko uses a number lock mechanism and therefore offers a useful and practical outdoor solution that is easy to implement.

Integrating Products Into Everyday Life

No product exists in an empty space. Only its usage in everyday life shows the value of a product: How useful it is and how well it fits into our life.

Every product has a social compound. No matter how well it functions it also has to be integrated into its natural surroundings. For this reason, in a design process it helps to look at and analyze product interaction: Which items will the product come into contact with in its daily life?

Just imagine a USB flash drive: Conceptualized to transport data easily and designed to be carried around all the time – just like a key ring. So why not combine these two things in a practical union? A pen drive that can be securely attached to a key ring is always at hand – You won‘t have go looking for the thing anymore: A simple but practical combination that spares users not only time but nerves as well.


The most compact geometrical form is a sphere. From a mathematical point of view a sphere has a maximum volume combined with a minimal surface. Therefore, it is no surprise that every mplanet is spherical. But does this mean every product should be designed like this as well? Hardly practical.

Compact forms should be tailored according to the function of a product. At the same time feasibility cannot be neglected - particularly with complex products it is helpful to calculate the volume of the different parts involved. Then the various volumes can be combined with each other, like in a complex puzzle resulting in the most compact total capacity. That compactness can be a key factor for success has been proven by the design of the famous Swiss pocketknife, which combines a multiplicity of different practical tools in a very small space. This has made the pocketknife a huge export success. The trick is quite simple: The knife is this compact because every element can be folded and stored inside it. The same principle can work with other products as well. Space can be saved with telescopic constructions, swing out mechanisms, interfolding designs and other flexible systems. Just imagine if we could not fold together an umbrella and so reduce it to a small part of its original size!

Combination of Functions

There are 2-in-1 shampoos, 2-in-1 notebook bags, 2-in-1 coats and many other 2-in-1 variations. To unite two different functions in one product has become a trend in recent years. The user enjoys buying only one instead of two products for a purpose: Saving money and space. Additionally, the combination of functions reduces the production and material expenses because the common components are just required once.

But there is always a catch somewhere. No wonder that there are still no combinations like a device that includes a razor and a mobile phone, or office chairs that can be used as beds, or toothbrushes with a voice recording function: A combination has to make sense. Both functions should somehow be compatible with each other.

Before joining two functions into one product remember the maxim: Marry in haste, repent at leisure. In other words never reduce the quality of a compound because in design, unlike math, two half things combined do not necessarily make a whole.

is an intelligent boxing glove. It supports athletes and helps them make progress via measuring the force and speed of the punches. A flexible screen based on OLED- technology visualizes the results. It comes with a specially developed app, that allows the user to not only measure their own progress but to compare their results with other athletes.

Easy Cleaning

Luckily our world is not as clean as many design catalogues would have us believe. After a very short time many products no longer look as glamorous as they did when new. Thinking about the effects of usage on a product before creating a design can avoid product degradation and user disappointment.

Generally there are a few points to consider:

Prevent unnecessary unevenness.
Smooth surfaces attract far less dirt and are far easier to clean. Decorative elements like grooves, holes, pores or waves do not only attract the attention of the viewer but also dust. One example: Many toothbrush handles have distinctive grooves, to give the impression they are easier to handle – a pseudo-function to distinguish it from other products in the same category. It really is a mystery how generations of teeth brushers managed to get by without the toothbrush slipping out of their hands before this incredible innovation came along. In reality, instead of actually providing a better grip, grooved handles only function as a magnet for toothpaste residue. Rest assured: A toothbrush without grooves will not be doomed to spend its life on the floor.

Give dirt no chance.
If you closely monitor smartphone users, you will often enough see them frantically wiping the screens and surfaces with their sleeves. A sign of their helpless and hopeless attempts to clean their fingerprints from the glass casing. Only that each attempt adds a new smear to the screen. With matt, sandblasted surfaces this problem could easily be solved. Dirt-repellent finishes keep products attractive for a long time.

Sometimes the so-called lotus effect could help: Dirt will simply drip off the surfaces. The principle was first discovered with the Asian lotus flower and today is used to keep the surfaces of clothes, cars and various other items dirt free, among them the glass façades of buildings.

Color and material
Suitably dressed.
To clean your cellar dressed all in white is impractical, to say the least. This principle can be applied to products. Sections that come into contact with dirt should be geared to these needs. Darker colors optically absorb dirt and make it nearly invisible. Smooth surfaces help to prevent dust and dirt from gaining a foothold in the first place. Extra layering can also stop foreign particles from getting lodged into surfaces and damaging their look.
In other words: A product should not only look new when fresh from the factory, but also look fresh after years in use.



People should feel comfortable enough to use certain products. Ergonomics is the science of optimizing the usability of devices. The term originates in the Greek words ergon (work or deed) and nomos (law, rule). Considering that most products are designed for human use, it is quite logical to adapt products to a human‘s needs – and not the other way round. With many products this does not seem to be the case. But why? Either ergonomic aspects are not seriously taken into consideration if at all, or many products are geared towards a core target group and a fine-adjustment does not seem profitable enough. Bad times for individualists.
Because humans are not only made of flesh and blood but also spirit and mind, ergonomics have to address two aspects – one physical and one mental.

The collapsible form makes beverage cans easier to recycle. This minimizes not only transportation costs to the recycling stations but also the costs for storage in advance. The width and radius of the can’s grooves are adjusted to the average finger size – for easier handling and a better grip.

Physical Ergonomics

Here human anatomy is clearly in the foreground. The physical ergonomics looks at the relations between humans and machines and optimizes product usability and handling. Even if you only think of ten people in your own circle of acquaintances, you will understand how hard it is to please everybody. Although there might be no panacea, there are certain methods that help to create good ergonomics.

Adaptation to the Average

Often it fits – often enough it does not.  
This method functions well with many products, but has disadvantages as well since there are always people outside the norm. Therefore these solutions are not optimal for every user. To give a good example: In automotive design the interior is constructed for a person with an average height of 1,70 metres. This reflects the average size of people all over the world. Too bad that people in the middle and northern regions of Europe are a bit taller than that: Here the average height is 1.80 metres. But adjusting car interiors to this size would reduce the sales figures in Asia and the Americas. Even the German automobile industry does not take the height of its fellow countrymen into account.

Adjustable Constructions

Better, but more expensive.
With this strategy the differences of product users are taken into account. For example: Height-adjustable computer screens. Every user can change the screen according to his or her height. Often enough producers opt to not take advantage of these sorts of options because, as mentioned above, of the additional costs. Instead they focus on an average value and deliberately give up on the small percentage that don‘t fit into this standard. When considering a flexible construction, the decision is dependent on how well a non-adjustable construction suits the target group and how expensive its realization is.

Flexible Solutions

Naturally individual.
This approach uses flexible materials and intelligent constructions to automatically adjust products to different situations. This saves a lot of time and effort. The adjustments normally happen continuously without any limitations or settings. In this field there are many good examples originating in living nature that have been developed by bionics. This might be the future in ergonomics: Smooth, individual automatic adjustments. The car seat constructions of Thomas Klawitter show how far such innovations could go: The designer and his team of engineers at BMW based his bionic seats on the anatomy and skeleton construction of trout. They have a clever body feature: When pushing against the side of a trout’s body the fin moves in the opposite direction. The same effect is used for the backs of car seats: When a human body is pressed into the seat due to higher speeds or curves the backrest automatically tightens its grip on the driver’s body and gives it better support. Additionally the headrest moves towards the head. Thanks to the bionics-based construction the innovative seat is not only very comfortable, but also lighter than other models. The smaller build also leaves more space for people sitting in the back.


Mental Ergonomics

This area is far less researched than the physical ergonomics of products. There are no one-fits-all patent solutions for this either. How people handle information, for example, is researched through perception and cognitive psychology. There is an important difference between what people see and what they later recognise, therefore the mental ergonomics are as important as the physical. For instance: When a person looks at a tree, the plant projects thousands of individual leaves on a man‘s retina. He, however, does not see individual leaves but sees the tree in its entirety. Relevant brain research has proven particularly useful in optimizing cognitive ergonomics and is often applied, among other things, to interface design.

A practical application for mental ergonomics
Imagine you have to depict the numbers 0 to 12 not in numbers but bars. Smaller numbers like 4 and 5 can be pictured easily and without error. With the larger amounts more mistakes appear; the error rates increase in disproportion to the visualized number. Dividing the numbers into smaller groups gives a better outline and provides a faster and more accurate readout. The Neolog watch uses this simple principle and visualizes time in its natural form. Even though it shows each minute it stays concrete and objective. Time is divided into hours, ten-minute steps and minutes. Thanks to groupings of three the time can be read quite easily.

The time is shown in amounts without being abstract. The perception of the neologian scale is like that of an hourglass, but additionally is very precise and fast to grasp. Depicted time: 6:24.

Once the wearer gets used to it the display provides an unusual and instinctive grasp of time.
Are mental ergonomics the same for everyone? No. Many of our features have been developed over centuries of evolution; people have certain common characteristics all over the world. Nonetheless, cognitive ergonomics are a flexible part of the creation of products since every human being is the result of his or her individual experiences. No study in the world could hope to gather all this data, so it remains something personal. The basis for these experiences lies in an individual’s biography and cultural background. The cultural aspect can at least be taken into consideration. Just imagine designing a dining table for the Asian market. Then it would be good to know that people in these cultural circles prefer to sit on the floor while eating. The personal aspects are of course far more complex and can only be guessed at. Next to the normal adjustment possibilities a subsequent flexible adaptation to the user’s preferences plays an important role. Therefore measuring and regulation techniques for individual behavior and a systematic adaptation in the design process are necessary. Good examples of this can be found in newly developed musical apps. These small programs learn more and more information about the music preferences and habits of users. This allows for the creation of individual playlists and a generation of suggestions for similar music. It is a possible that these apps will one day know us better than we know ourselves.

The texts are excerpts from the book "360° Industrial Design" by the author Arman Emami, published 2014, niggli Verlag