The Power of Nine in a Converged Environment
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Presentation given at NESTA Futurelab for 3G Phones: Innovations Workshop
Date: 07/06/2005
Venue: Bristol, UK
Article
Engineers are very good at working out how to develop new technologies but the user interface experience and information design are far behind. Just think for a moment about your user interface experience:
Keypads
- Non standard television remote controllers which are quite different from
- Non standard hi-fi remote controllers; which are quite different from
- Car CD/radio panels; which are far different from
- ATM panels; which are quite different from
- Non standard cell phone keypads and menu systems.
Since the departure of the valve radio and the circular analogue telephone dial, we have got precisely nowhere.
Now think about the information design which might make life easier for everyone if we could only get the user interface experience into some logical shape. Imagine your favourite web site and ask yourself the question; how would I navigate this using my mobile phone keys instead of a mouse?
The problem here is simple. Although technologies are converging rapidly so that we will soon be receiving high definition television over a broad band enabled internet so that, for all intents and purposes, the telephone the television and broadcasting will have merged, most information is still being designed for the qwerty and mouse driven PC system. The honourable exception is the Sky Electronic Programme Guide which is a grid that can be easily traversed vertically for channel and horizontally for time. Alternatively, it has an intuitive genre taxonomy.
This dearth of forward thinking will involve information creators, designers, aggregators and brokers in heavy and quite unnecessary expense.
One of the high level principles of information design is this:
Enable Choice
- Enable choice of channel and user interface
Now this could be achieved by subjecting data to massive automated re-rendering as it is called across different channels for use with different interfaces but the ideal is a basic, simple, elegant, functional design. That design, I want to suggest, should be based on what I call the Power of Nine, an idea I developed five years ago with the late lamented Roy Stringer. Put simply, this calls for all high level taxonomy to be limited to nine elements.
There are five very good reasons for this strategy:
PO9 Rationale
- First of all, and by far the most important, this taxonomical limitation accords with the basic rule of (7 + or - 2) which states that in making a choice from a large number of elements the smallest number of viable classes is 5 and the largest number of retainable classes is 9; and so nine is the upper limit in an options array
- Secondly, nine accords with the natural string of single digits in our numbering system
- Thirdly, this taxonomy fits neatly into the telephone numeric keypad and other numeric keypads such as digital radios with screens
- The combination of the keypad and the single digits in our numeric system provide the maximum choice for single keying
- Fourthly about 1/3 of the population will not use a qwerty/mouse driven device
- Finally, this system is ideal for voice in transactions.
In summary, then, the Power of Nine is psychologically and ergonomically optimal and intuitive.
How might this work?
Here is an example of how it might work for community information:
Top Level Taxonomy
|
1 Arts/Entertainment |
2 Belief |
3 Community |
|
4 Council |
5 Ed/Training |
6 Health |
|
7 Shopping |
8 Social Services |
9 Transport/Tourism |
|
* |
0
|
# |
The array is shown alphabetically but it would alter according to usage so that the most popular elements would occupy 1 and 5.
Now let us look at the next level down. You are driving your car into town and you call up this interactive information site using your hands free mobile. You press 1 for Arts and Entertainment:
Second Level Taxonomy - Arts/Ent
|
1 Tonight |
2 Cinema |
3 Clubs/Bars |
|
4 Theatre |
5 Box Office |
6 Music/Dance |
|
7 Food |
8 Fringe |
9 Fitness/Therapy |
|
* |
0
|
# |
Notice that the two booking facilities are at 1 and 5; that might be the result of a payment rather than user ranking.
The driver, who is used to this numbering system, simply calls "One" into his phone to see what tickets are available for tonight; the automatic system asks him what he wants using the same numbers, so if he wants cinema tickets tonight he calls "Two".
Here is another example. A tourist in a hotel wants to go to church and presses 2 on her top level array for "Belief". This is what she sees:
Second Level Taxonomy - Belief
|
1 C of E |
2 R.C. |
3 Islam |
|
4 Christian |
5 Today |
6 Hindu |
|
7 Sikh |
8 Zoroastrian |
9 Buddhist |
|
* Back |
0 Other |
# Enter/Execute |
Our tourist is a pagan, so she presses 0 for "Other" and is offered a secondary list.
Another tourist presses 1 for C of E and is presented with a list of 56 churches; he can use sms to indicate the name of the church whose page he wants to look at.
When we wrote the Power of Nine SMS was only just beginning and our strategy then was to group lists into nines with the use of the zero key to call up the next nine; but SMS is clearly widely used, even by those who will not use a qwerty keyboard.
This system only uses the ten digits with 0 for "Other", the star for going up a level and the hash for entering or executing; this turns the array into a payments user interface.
What you have here, then, is a system which obeys the high level rule I mentioned at the beginning:
- Enable choice of channel and user interface
The system has also been designed to obey a second high level rule
Multi Modal
- Create multi modally
This means that the system:
- Presents in text, pictures and audio
- Receives in text and audio.
It will not be long before it also understands gesture but we are not there yet.
Which only leaves one more high level principle which I have put at the top of the summary of all three:
High Level Digital Design principles
- Enable customisation and simplification
- Enable choice of channel/user interface
- Create multi modally
This first principle means that the user can choose such features as colour foreground and background, print size and font, removal of graphics, sound volume etc.
So, there you have it, an elegant system based on the Power of Nine and on three simple, high level principles.