Usability = Predictability

24 May 2008 - 7:54pm
6 years ago
61 replies
3403 reads
Robert Hoekman, Jr.
2005

"Usability equals predictability."

As in, if you can accurately predict what's going to happen next in an
interaction, it's because the action you're taking is understandable, clear,
logical, makes you feel confident, etc. If you can accurately predict what's
next, the interaction has high usability. If you can't accurately predict
what's next, the interaction has low usability.

Shoot holes in that statement.
-r-

Comments

24 May 2008 - 9:53pm
Todd Moy
2007

Robert - no holes to shoot in that argument. Actually, when I was asked in
an interview about what I found most important in an interface, I answered
with that same word - predictability.

-Todd

On Sat, May 24, 2008 at 8:54 PM, Robert Hoekman Jr <robert at rhjr.net> wrote:

> "Usability equals predictability."
>
> As in, if you can accurately predict what's going to happen next in an
> interaction, it's because the action you're taking is understandable,
> clear,
> logical, makes you feel confident, etc. If you can accurately predict
> what's
> next, the interaction has high usability. If you can't accurately predict
> what's next, the interaction has low usability.
>
> Shoot holes in that statement.
> -r-
>
>

24 May 2008 - 9:09pm
rui ramos
2008

Beautiful, I totally agree with that.

Except that we can always take it one step further: providing capabilities
the user is not even expecting that would be possible in order to make their
experience easier and more direct. Take the Gmail's
auto-complete-fields-from-contact-list-addresses as an example.

Rui Ramos

24 May 2008 - 10:39pm
Itamar Medeiros
2006

One could argue that -- given a context -- "disruption" can
actually be good: if things are too predictable, sudden changes of
patterns can grab people's attention back.

I remember watching this interview by Bruce Sterling
(http://www.technologyreview.com/video/design) when his talking about
design... the interview all brilliant, but the piece I wanted to
brought up was this:

"I went down once into the accelerator in cern in geneva. and when
we were driving around the accelerator ring in an electric golf cart
and the guy was explaining that they are out, you know, pursuing the
pi meson or whatever, he said, you know quite often we have accidents
down here because, people are driving the 27km line of this tube and
they just zone out and crash into the wall, so I said why don%u2019t
you just put in some murals to break the visual monotony, and he just
starred like I had come from mars, and I said look, its lit 24 hours
right, why don%u2019t you put in some house plants, I mean just kind
of humanize the interface a little bit, I mean this is so punishingly
monotonous that you are actually harming people. the guy%u2019s brain
couldn%u2019t go there, its a physics instrument, you can%u2019t
paint it!%u201D

Ok, putting in simple words "If predictability (when is NOT
monotony!) = Usability!

{ Itamar Medeiros } Information Designer
http://designative.info/
http://www.autodesk.com/

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Posted from the new ixda.org
http://www.ixda.org/discuss?post=29451

25 May 2008 - 12:13am
Robert Hoekman, Jr.
2005

>
> Predictability, "works", and "meets a real current human need" is best of
> all.
>

Seems to me that "works" is enveloped by the idea of attaining an expected
result. If it didn't work, you wouldn't get what you expected.

And "meets a real current human need" relates to the value proposition, not
whether or not someone can use it or the degree to which it is usable.

(By the way, the game is: you attack, and I deflect.) :)

-r-

25 May 2008 - 12:15am
Chauncey Wilson
2007

Predictability is one important attribute of usability for most
products; however, if you are a game designer, then unpredictability
is important for posing gamers with some challenge.

Chauncey

On Sat, May 24, 2008 at 10:09 PM, Rui Miguel Ramos <ruiramos at gmail.com> wrote:
> Beautiful, I totally agree with that.
>
> Except that we can always take it one step further: providing capabilities
> the user is not even expecting that would be possible in order to make their
> experience easier and more direct. Take the Gmail's
> auto-complete-fields-from-contact-list-addresses as an example.
>
> Rui Ramos
> ________________________________________________________________
> Welcome to the Interaction Design Association (IxDA)!
> To post to this list ....... discuss at ixda.org
> Unsubscribe ................ http://www.ixda.org/unsubscribe
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25 May 2008 - 12:23am
Kontra
2007

> "Usability equals predictability."

Not everything that's usable is predictable and not everything that's
predictable is usable.

--
Kontra
http://counternotions.com

25 May 2008 - 12:24am
Robert Hoekman, Jr.
2005

>
> Predictability is one important attribute of usability for most
> products; however, if you are a game designer, then unpredictability
> is important for posing gamers with some challenge.

We may be talking about 2 different things, though. If you're playing a
video game and you shoot a guy in the chest and he dies a dramatic death and
hands a grenade to another bad guy before falling 12 floors to his last
breath, that would be an unpredictable event, and would certainly add to the
enjoyability and challenge of the game.

If, on the other hand, nothing happened after shooting him in the chest,
well, that would be a usability issue.

Eh?

-r-

25 May 2008 - 12:25am
Robert Hoekman, Jr.
2005

>
> Not everything that's usable is predictable and not everything that's
> predictable is usable.

Examples?

-r-

25 May 2008 - 12:38am
Robert Hoekman, Jr.
2005

>
> One could argue that -- given a context -- "disruption" can
> actually be good: if things are too predictable, sudden changes of
> patterns can grab people's attention back.
>

Fantastic point! Let's see where it takes us (thinking out loud now) ...

So, under what circumstances do we need to grab their attention back? I
suppose a system error could be a good reason. I doubt many people expect or
desire system errors.

But if there's a system error, isn't that a usability issue? As in, if a
system error occurs when I was expecting something else, then doesn't that
mean the system is less usable than it should be? Is system reliability is
part of usability? (Seems so, but are there arguments that this is not the
case?)

In Bruce Sterling's example, the lack of scenery caused people to daze out
and crash, presumably because the scenery was too predictable. Leading
people to crash would be a definite usability issue, I'd say. And in that
case, predictability seemed to cause it. Unpredictability — in this case,
some texture in the design — could have prevented lots of crashes.

However, one could argue that the golf cart driver's prediction should be
being able to get through the 27km line of tube without crashing. "I predict
I will get through this unharmed" seems like a perfectly reasonable
statement to make. How hard is it to drive a golf cart, after all?

Hmm.

Thoughts? There's definitely something to your argument, and I'd like to
explore it more.

-r-

25 May 2008 - 7:40am
Chauncey Wilson
2007

I'm thinking out loud a bit myself this morning. Pulled a late night
work on chapters about the QOC method and the use of cause and effect
diagrams in UCD. A key issue here is that we often speak of
"usability" as a single thing when it has many different attributes.

This is tricky since usability is a general term and usability has
many different attributes or dimensions, with predictability being one
of those. Usability or more broadly user experience attributes can
interact with one another. For example, in studies of what makes a
system usable, response time often bubbles to the top of the list
(actually, it is often in the top 3). You could have a system that
everyone can learn easily (initial learning) but poor performance
(average response time or variability in response time) might make a
system that is usable in one dimension, unusable overall. The ISO
definition has effectiveness, efficiency, and satisfaction, the
basics, but there are many more dimensions to usability that have been
considered since the 1980s based on work by Whiteside, Bennett, Gould,
and other early proponents of usability engineering, some that overlap
broadly. So in the statement below, you could replace "usable" with
any one of a number of dimensions and compare it to predicability and
examine relationships among different usability attributes.
As Itamar noted, unpredicability can be good in some circumstances and
human factors engineers have done a lot research into factors that
affect vigilance in sustained-attention tasks. Wylie and Mackie in
the late 1980s suggested that a system be injected with artificial
signals and then the operators would get feedback on their detection
performance.

One of the issues that hinders our fields is that we fail to think of
usability in our day-to-day work as have many dimensions with some
dimensions being more critical in a particular context than others.
The simplest example is a system where some people use a feature once
a month while others use it 50 times a day. Many people speak of
consistency in a user interface as promoting usability but if you have
a bi-modal distribution, you may need two interaction methods to be
consistent with the way people work. The principles of being
inconsistent to be consistent is a difficult one for many corporations
who decree that "all our products will be consistent visually and have
only one way to perform a task (which gets into another topic of
redundancy which is another good debate). Grudin published what I
think is a classic paper that got into the subtleties of consistency
(often considered an attribute of a usable system) and noted that to
be consistent with how people work, you might need to design systems
that have inconsistencies (as well as multiple ways to do things).
The Grudin paper uses old examples, but the issue is still as strong
as ever. For a good read see The Case Against User Interface
Consistency by Jonathan Grudin at
http://research.microsoft.com/users/jgrudin/publications/consistency/CACM1989.pdf

This is a good topic since I think that an explicit definition of
"usability" is critical to each project that we work one; listing the
attributes of usability that are most critical to success of a product
(learnability, efficiency, prevention of errors, flexibility,
predictability, fun, memorability (critical for systems used
infrequently like tax software) satisfaction, performance, ....). I
often hear people referring to "usability" and they are each defining
it differently which can create problems throughout the product design
and development cycle.

Chauncey

On Sun, May 25, 2008 at 1:25 AM, Robert Hoekman Jr <robert at rhjr.net> wrote:
>>
>> Not everything that's usable is predictable and not everything that's
>> predictable is usable.
>
>
> Examples?
>
> -r-
> ________________________________________________________________
> Welcome to the Interaction Design Association (IxDA)!
> To post to this list ....... discuss at ixda.org
> Unsubscribe ................ http://www.ixda.org/unsubscribe
> List Guidelines ............ http://www.ixda.org/guidelines
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>

25 May 2008 - 9:27am
Eric Scheid
2006

On 25/5/08 10:54 AM, "Robert Hoekman Jr" <robert at rhjr.net> wrote:

OK, I'll bite.

> "Usability equals predictability."

as in you click a link/button/image on a web page, and you predict that it
will ... what? ... load a new page completely replacing the current page, or
do some AJAX stuff to update just a part of the page?

"predictability" = no changes from what is current expectations = no
evolution of ui standards = we'd be stuck with the usability from the 1980's
technology, not what we've got now.

no?

e.

25 May 2008 - 1:55am
Sharon Greenfield5
2008

One example would be someone who has never used a computer before,
let's say a small child around the age of 4.
Let's say it's an iPhone to be specific.

I would not use the term 'predictable', even though the interface is
very usable.

I would use the term 'intuitive'.

On May 24, 2008, at 10:25 PM, Robert Hoekman Jr wrote:

>>
>> Not everything that's usable is predictable and not everything that's
>> predictable is usable.
>
>
> Examples?

25 May 2008 - 4:49am
robenslin
2008

Hi Robert, this equation/statement is faultless. It's good, however,
to remind ourselves of it from time-to-time. Often we get carried
away and wonder off on a tangent. I see this statement as a
're-set' function for all involved in usability.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Posted from the new ixda.org
http://www.ixda.org/discuss?post=29451

25 May 2008 - 12:27pm
Robert Hoekman, Jr.
2005

>
> On the value proposition: some people separate "usable" (able to complete a
> task) and "useful" (able to complete the required task at the required time
> in the required place).

But that's not the definition of "useful". Useful simply means to be of use,
does it not? There is definitely a separation. Something can be usable
without being useful, and vice-versa. I can use a wristwatch pretty well,
but I have no need for one.

Considering a thing/system/site outside of its context of use (i.e. where it
> needs to be useful) is responsible for much misery - some bloke I sat and
> listened to the other day (he looked a lot like you, only older) mentioned a
> police dispatch/alert system that failed because the users didn't want to be
> finding the control key while being shot at - go figure :)
>

I'm not considering a thing outside of its context, just exploring whether
or not these two terms are synonyms or not.

I'm not sure what you meant, "looked a lot like you, only older", but I'll
assume it wasn't meant negatively.

For the record, something about "usability = predictability" has bothered me
since I first saw it written yesterday. I'm playing devil's advocate here to
see if it holds up. I don't think it does. I'm relying on the IxDA community
to come up with all those crafty arguments that make it fall apart.

I tossed this out to the Twitterverse last night as well. The most practical
reply I got? Slot machines. Definitely usable while unpredictable.

The best answer? Women. (Crass, perhaps, but funny. Apologies.)

-r-

25 May 2008 - 12:36pm
Robert Hoekman, Jr.
2005

>
> "predictability" = no changes from what is current expectations = no
> evolution of ui standards = we'd be stuck with the usability from the
> 1980's
> technology, not what we've got now.
>
> no?

No. I simply mean that if you, say, click a link on a web page, predicting
that it will land you on the About Us page, and it does indeed land you on
that page, then that would be deemed to have a high level of usability.

Likewise, if you click a command link or button—regardless of whether it
triggers an Ajax function or loads a new page or whatever—as long as you can
predict the result (not the UI result, but the net result), then it's
usable. For example, you click a Save button believing it will save whatever
you've been working on. It doesn't matter if the resulting success indicator
is on another page or the same one, what matters is that you were able to
accurately and correctly predict what effect the button would have.

If the interaction is clear and understandable, it doesn't matter if it's an
old classic or brand new and revolutionary. The subject line of this thread
refers only to whether or not you can predict the outcome.

You can innovate all you want as long as what you design is understandable
and the outcome predictable, can you not?

Of course, as we've already seen, not all things must be predictable to be
usable, so this is all a moot point now. :) Again, just playing devil's
advocate here.

-r-

25 May 2008 - 12:42pm
martinpolley
2007

Things can be predictable without being usable. Any tech writer who has ever
had the misfortune to have to write in Word will tell you that it screws up
numbered lists. It does this in an annoyingly predictable way. Usable it is
not.

Cheers,

Martin Polley

25 May 2008 - 12:53pm
Jack L. Moffett
2005

Predictability is in large part a result of past experience. When an
interface does something in a new way that makes a task easier or adds
value to the result, it is doing something unpredictable and
increasing usability. What better way to satisfy a user than to
pleasantly surprise them?

Jack

Jack L. Moffett
Interaction Designer
inmedius
412.459.0310 x219
http://www.inmedius.com

There is no good design that is not
based on the understanding of people.

- Stefano Marzano
CEO of Philips Design

25 May 2008 - 5:08pm
Anonymous

I've run user tests where I'll sit someone in front of a screen and before I give them a task, or even let them touch anything, I ask them to predict what each element of the interface will do. Sometimes nuanced problems are picked up this way which might otherwise be missed.

I'm guessing this is a pretty common thing to do in user testing (standard practice even? I'm emphatically not an expert...). Either way, I've found it useful. And it's based on the assumption - correct I think - that a big chunk of usability can be equated with predictability.

I don't think that predictability and innovation are mutually exclusive either. The "predictability test" can still be a good litmus for a genuinely new interaction - or at least for a good one. After all, aren't the greatest design innovations the perfect amalgamation of original compostion and familiar metaphor? Something can be both completely surprising and utterly "right" (= predictable) at the same time.

25 May 2008 - 4:58pm
Jeff Garbers
2008

This is an intriguing discussion, but I fear "Usability =
Predictability" is a bit of an oversimplification. So just to
antagonize...

Consider an application with 150 functions. The UI for this application
consists of a single screen, with a short sentence describing each
function in 6pt text. There is a 8x8 pixel green button next to each
sentence. Instructions at the top of the screen say "Click the green
button next to the function you wish to perform."

Assume the text completely explains the function so any user can
understand it, and when they click the tiny green button they get
exactly the function they expect from the description of the function.

This UI strikes me as 100% predictable, but I doubt any of us would
consider it usable.

So, it seems to me that as elegant as the original equation is, we might
need something more along the lines of

findability + accessibility + predictability = usability

Anybody want to add some more terms to the equation?

25 May 2008 - 5:11pm
Kontra
2007

> Anybody want to add some more terms to the equation?

Design is design?

--
Kontra
http://counternotions.com

25 May 2008 - 5:13pm
SemanticWill
2007

Brilliant, insightful tautology, mate!

On Sun, May 25, 2008 at 6:11 PM, Kontra <counternotions at gmail.com> wrote:

> > Anybody want to add some more terms to the equation?
>
> Design is design?
>
> --

25 May 2008 - 5:11pm
SemanticWill
2007

Yes... and this to some degree borrows from Peter Hong, an amazing UX guy
now at Google.

Take
findability + accessibility + predictability = usability,

But add in emotional appeal, because as we all know, having read Norman's
Emotional Design, that products, services, things, that garner an emotional
response, people consider more usabile, whether they are - or not.

And from Peter:
"The 'j' factor was inspired by Milton Glaser's life lesson #5... which
beautifully offers that "Less is not necessarily More", rather...

"Just enough is More"

'Just enough' of what matters to our lives so that the experience feels
wonderfully satisfying. In life, there never is a set formula."

f(j)+a(j)+p(j)/l + e(1-c)= u

e = emotional appeal
f = findability
p = predictability
l = learnability
c = cost

That is my 2 cents :-)

- Will

On Sun, May 25, 2008 at 5:58 PM, Jeff Garbers <jgarbers at xltsoftware.com>
wrote:

> This is an intriguing discussion, but I fear "Usability =
> Predictability" is a bit of an oversimplification. So just to
> antagonize...
>
> Consider an application with 150 functions. The UI for this application
> consists of a single screen, with a short sentence describing each
> function in 6pt text. There is a 8x8 pixel green button next to each
> sentence. Instructions at the top of the screen say "Click the green
> button next to the function you wish to perform."
>
> Assume the text completely explains the function so any user can
> understand it, and when they click the tiny green button they get
> exactly the function they expect from the description of the function.
>
> This UI strikes me as 100% predictable, but I doubt any of us would
> consider it usable.
>
> So, it seems to me that as elegant as the original equation is, we might
> need something more along the lines of
>
> findability + accessibility + predictability = usability
>
> Anybody want to add some more terms to the equation?
>
> _______________
>

25 May 2008 - 5:46pm
Chauncey Wilson
2007

Your equation, taken as a heuristic, is quite good and illustrates
that usability (or user experience) is multi-dimensional. This
heuristic equation will have different terms for different categories
of product, but it makes the point that we should be more specific
when we speak of "the usability of the product".

There is an equation called "Baker's Equation" that is somewhat
similar, but focused on the liklihood of success of assistive
technologies.

S = M/(P+C+L+T)
Where

S = Liklihood of success
M = disabled person's motivation to complete a task
P = the physical effort required to complete a task
C = the cognitive effort required to complete a task
L = the linguistic effort required to complete a task
T = The amount of time required to activate and control a device.

Chauncey

> Take
> findability + accessibility + predictability = usability,
>
> But add in emotional appeal, because as we all know, having read Norman's
> Emotional Design, that products, services, things, that garner an emotional
> response, people consider more usabile, whether they are - or not.
>
> And from Peter:
> "The 'j' factor was inspired by Milton Glaser's life lesson #5... which
> beautifully offers that "Less is not necessarily More", rather...
>
> "Just enough is More"
>
> 'Just enough' of what matters to our lives so that the experience feels
> wonderfully satisfying. In life, there never is a set formula."
>
> f(j)+a(j)+p(j)/l + e(1-c)= u
>
> e = emotional appeal
> f = findability
> p = predictability
> l = learnability
> c = cost
>

25 May 2008 - 8:55pm
Anonymous

The best answer? Women. (Crass, perhaps, but funny. Apologies.)

I counter that Men are predictable but not usable.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Posted from the new ixda.org
http://www.ixda.org/discuss?post=29451

25 May 2008 - 9:37pm
Steve Baty
2009

Can I just say that some of the Usability 'equations' proffered to this
thread bring tears to my eyes.

I look at this statement in terms of defining a causal relationship between
usability & predictability. Or defining a set relationship. Essentially,
Robert is saying that "everything which is usable is also predictable; and
everything which is predictable is also usable." Some examples have already
been provided that show the second part of the statement is incorrect - that
some systems are alarmingly predictable in the way they suck.

So, we're left with "everything which is usable is also predictable". A
longer version of this statement might be: "an inherent characteristic of a
usable system is that it behaves in a predictable manner in response to user
interaction." Implied in this statement is that little or no learning should
be necessary, although Robert does not explicitly make that constraint
clear. Some have argued already that a system which is predictable in the
first instance could better be characterised as intuitive rather than
usable.

Perhaps then we're looking to support the statement that: "*an inherent
characteristic of a usable system is that, in response to user interaction,
it behaves in a manner predictable by nominally experienced people*". Which
now starts to introduce the notion of a continuum of predictability and
usability which varies according to the experience of the user.

Since, as a discipline, we tend to believe in the notion that completely
novice users should be able to approach a system interface and interact
meaningfully with it, we - in theory at least - support the notion of
usability in the absence of predictability. In other words, the
predictability or lack thereof is a characteristic of the user, not the
system.

We might then better characterise the relationship between usability and
predictability as such: "an inherent characteristic of a usable system is
that, in response to user interaction, it behaves in a manner that can be
predicted with reasonable certainty by a person moderately experienced in
the use of the same or similar systems".

To put this in more succinct terms: "usability => consistency". And note
that the relationship is one-way.

Steve

2008/5/25 Robert Hoekman Jr <robert at rhjr.net>:

> "Usability equals predictability."
>
> As in, if you can accurately predict what's going to happen next in an
> interaction, it's because the action you're taking is understandable,
> clear,
> logical, makes you feel confident, etc. If you can accurately predict
> what's
> next, the interaction has high usability. If you can't accurately predict
> what's next, the interaction has low usability.
>
> Shoot holes in that statement. <http://www.ixda.org/help>
>

------------------------------------------------
Steve 'Doc' Baty B.Sc (Maths), M.EC, MBA
Principal Consultant
Meld Consulting
M: +61 417 061 292
E: stevebaty at meld.com.au

UX Statistics: http://uxstats.blogspot.com

Member, UPA - www.upassoc.org
Member, IA Institute - www.iainstitute.org
Member, IxDA - www.ixda.org
Contributor - UXMatters - www.uxmatters.com

25 May 2008 - 11:44pm
Eric Scheid
2006

On 26/5/08 3:36 AM, "Robert Hoekman Jr" <robert at rhjr.net> wrote:

>> "predictability" = no changes from what is current expectations = no
>> evolution of ui standards = we'd be stuck with the usability from the
>> 1980's technology, not what we've got now.
>>
>> no?
>
> No. I simply mean that if you, say, click a link on a web page, predicting
> that it will land you on the About Us page, and it does indeed land you on
> that page, then that would be deemed to have a high level of usability.
>
> Likewise, if you click a command link or button‹regardless of whether it
> triggers an Ajax function or loads a new page or whatever‹as long as you can
> predict the result (not the UI result, but the net result), then it's
> usable. For example, you click a Save button believing it will save whatever
> you've been working on. It doesn't matter if the resulting success indicator
> is on another page or the same one, what matters is that you were able to
> accurately and correctly predict what effect the button would have.

I wouldn't classify that as "predictable", that's more "satisfying". You
wanted something, you did something, you got the result you wanted.
Satisfaction.

e.

26 May 2008 - 1:45am
David Drucker
2008

Of course, there are rare cases of some things that are quite usable
but aren't that predictable. I can think of some 'toys' that delight
in their unpredictable nature:

The Wolfram Tones music generator (http://tones.wolfram.com/generate/)
can produce quite variable and unexpected musical passages, many which
are hard to predict with any precision.

A flash toy, for creating snowflakes (http://www.zefrank.com/
snowflake/) while only partly predictable, can produce some lovely
animations, but one's control over the UI is something that would have
to be developed over time.

Someone might argue that these are not 'usable' because they are
merely toys. How churlish of you...

Of course, the UIs behind these toys is pretty good, because the
instant feedback from them invites experimentation.

Justing injecting some whimsy into this serious discussion...

-David Drucker
david at drucker.ca

On 25-May-08, at 7:37 PM, Steve Baty wrote:

> Can I just say that some of the Usability 'equations' proffered to
> this
> thread bring tears to my eyes.
>
> I look at this statement in terms of defining a causal relationship
> between
> usability & predictability. Or defining a set relationship.
> Essentially,
> Robert is saying that "everything which is usable is also
> predictable; and
> everything which is predictable is also usable." Some examples have
> already
> been provided that show the second part of the statement is
> incorrect - that
> some systems are alarmingly predictable in the way they suck.
>
> So, we're left with "everything which is usable is also
> predictable". A
> longer version of this statement might be: "an inherent
> characteristic of a
> usable system is that it behaves in a predictable manner in response
> to user
> interaction." Implied in this statement is that little or no
> learning should
> be necessary, although Robert does not explicitly make that constraint
> clear. Some have argued already that a system which is predictable
> in the
> first instance could better be characterised as intuitive rather than
> usable.
>
> Perhaps then we're looking to support the statement that: "*an
> inherent
> characteristic of a usable system is that, in response to user
> interaction,
> it behaves in a manner predictable by nominally experienced
> people*". Which
> now starts to introduce the notion of a continuum of predictability
> and
> usability which varies according to the experience of the user.
>
> Since, as a discipline, we tend to believe in the notion that
> completely
> novice users should be able to approach a system interface and
> interact
> meaningfully with it, we - in theory at least - support the notion of
> usability in the absence of predictability. In other words, the
> predictability or lack thereof is a characteristic of the user, not
> the
> system.
>
> We might then better characterise the relationship between usability
> and
> predictability as such: "an inherent characteristic of a usable
> system is
> that, in response to user interaction, it behaves in a manner that
> can be
> predicted with reasonable certainty by a person moderately
> experienced in
> the use of the same or similar systems".
>
> To put this in more succinct terms: "usability => consistency". And
> note
> that the relationship is one-way.
>
> Steve
>
> 2008/5/25 Robert Hoekman Jr <robert at rhjr.net>:
>
>> "Usability equals predictability."
>>
>> As in, if you can accurately predict what's going to happen next in
>> an
>> interaction, it's because the action you're taking is understandable,
>> clear,
>> logical, makes you feel confident, etc. If you can accurately predict
>> what's
>> next, the interaction has high usability. If you can't accurately
>> predict
>> what's next, the interaction has low usability.
>>
>> Shoot holes in that statement. <http://www.ixda.org/help>
>>
>
> ------------------------------------------------
> Steve 'Doc' Baty B.Sc (Maths), M.EC, MBA
> Principal Consultant
> Meld Consulting
> M: +61 417 061 292
> E: stevebaty at meld.com.au
>
> UX Statistics: http://uxstats.blogspot.com
>
> Member, UPA - www.upassoc.org
> Member, IA Institute - www.iainstitute.org
> Member, IxDA - www.ixda.org
> Contributor - UXMatters - www.uxmatters.com
> ________________________________________________________________
> Welcome to the Interaction Design Association (IxDA)!
> To post to this list ....... discuss at ixda.org
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Vancouver, BC

david at drucker.ca

26 May 2008 - 8:01am
Todd Warfel
2003

On May 24, 2008, at 8:54 PM, Robert Hoekman Jr wrote:

> "Usability equals predictability."
>
> As in, if you can accurately predict what's going to happen next in
> an interaction, it's because the action you're taking is
> understandable, clear, logical, makes you feel confident, etc. If
> you can accurately predict what's next, the interaction has high
> usability. If you can't accurately predict what's next, the
> interaction has low usability.

We have a number of guiding principles we design by. One of them is
"Predict before you click." And it's one of our most commonly referred
to principles for the very reasons you highlight above.

Cheers!

Todd Zaki Warfel
President, Design Researcher
Messagefirst | Designing Information. Beautifully.
----------------------------------
Contact Info
Voice: (215) 825-7423
Email: todd at messagefirst.com
AIM: twarfel at mac.com
Blog: http://toddwarfel.com
Twitter: zakiwarfel
----------------------------------
In theory, theory and practice are the same.
In practice, they are not.

26 May 2008 - 8:01am
Todd Warfel
2003

On May 25, 2008, at 1:23 AM, Kontra wrote:

> Not everything that's usable is predictable and not everything that's
> predictable is usable.

For example?

Cheers!

Todd Zaki Warfel
President, Design Researcher
Messagefirst | Designing Information. Beautifully.
----------------------------------
Contact Info
Voice: (215) 825-7423
Email: todd at messagefirst.com
AIM: twarfel at mac.com
Blog: http://toddwarfel.com
Twitter: zakiwarfel
----------------------------------
In theory, theory and practice are the same.
In practice, they are not.

26 May 2008 - 8:04am
Todd Warfel
2003

On May 25, 2008, at 10:27 AM, Eric Scheid wrote:

> "predictability" = no changes from what is current expectations = no
> evolution of ui standards = we'd be stuck with the usability from
> the 1980's
> technology, not what we've got now.
>
> no?

No. Predictability means you before you perform an action, you can
assert with a good degree of accuracy what will happen next. We've
seen this with Tags. While most participants haven't got a clue what
those things are, they think, or predict, that what will happen if
they click on one is that they will see a list of items related to
that word. They've never seen tags before, but they can predict with a
high degree of accuracy what will happen next.

Cheers!

Todd Zaki Warfel
President, Design Researcher
Messagefirst | Designing Information. Beautifully.
----------------------------------
Contact Info
Voice: (215) 825-7423
Email: todd at messagefirst.com
AIM: twarfel at mac.com
Blog: http://toddwarfel.com
Twitter: zakiwarfel
----------------------------------
In theory, theory and practice are the same.
In practice, they are not.

26 May 2008 - 8:04am
Todd Warfel
2003

On May 25, 2008, at 1:42 PM, Martin wrote:

> Things can be predictable without being usable. Any tech writer who
> has ever
> had the misfortune to have to write in Word will tell you that it
> screws up
> numbered lists. It does this in an annoyingly predictable way.
> Usable it is
> not.

Unfortunately true.

Cheers!

Todd Zaki Warfel
President, Design Researcher
Messagefirst | Designing Information. Beautifully.
----------------------------------
Contact Info
Voice: (215) 825-7423
Email: todd at messagefirst.com
AIM: twarfel at mac.com
Blog: http://toddwarfel.com
Twitter: zakiwarfel
----------------------------------
In theory, theory and practice are the same.
In practice, they are not.

26 May 2008 - 8:31am
james horgan
2008

why is predicatability seen as a good or useful thing in todays competitive
market? useable design can be both surprising and fresh, and people want to
get on that learning curve just to try something new and play with a new
product.
usability is a basic part of a good design, but its the creativity of the
design that counts.

On Mon, May 26, 2008 at 9:04 AM, Todd Zaki Warfel <lists at toddwarfel.com>
wrote:

>
> On May 25, 2008, at 1:42 PM, Martin wrote:
>
> Things can be predictable without being usable. Any tech writer who has
>> ever
>> had the misfortune to have to write in Word will tell you that it screws
>> up
>> numbered lists. It does this in an annoyingly predictable way. Usable it
>> is
>> not.
>>
>
> Unfortunately true.
>
>
> Cheers!
>
> Todd Zaki Warfel
> President, Design Researcher
> Messagefirst | Designing Information. Beautifully.
> ----------------------------------
> Contact Info
> Voice: (215) 825-7423
> Email: todd at messagefirst.com
> AIM: twarfel at mac.com
> Blog: http://toddwarfel.com
> Twitter: zakiwarfel
> ----------------------------------
> In theory, theory and practice are the same.
> In practice, they are not.
>
> ________________________________________________________________
> Welcome to the Interaction Design Association (IxDA)!
> To post to this list ....... discuss at ixda.org
> Unsubscribe ................ http://www.ixda.org/unsubscribe
> List Guidelines ............ http://www.ixda.org/guidelines
> List Help .................. http://www.ixda.org/help
>

26 May 2008 - 8:50am
Fredrik Matheson
2005

As a means of facilitating this discussion, the slogan "usability =
predictability" has done a great job. Many assumptions, opinions and
convictions have been made visible and we might even have succeeded in
making some tacit knowledge explicit.
That being said, I'm always wary of slogans. By their nature, they swear
themselves to be true, but no argument (not even this one) can hold sway at
all times.

Slogans are a way of simplifying complex messages so that audiences can be
swayed. They do not seek to explain or enlighten and therefore come apart
during inspection.

Left unchecked, however, slogans get people into all sorts of situations
where they act against their better judgement. Just take a look at the
scrum-development list for a host of discussions where someone thinks they
can't do X or Y because of principle 1 or 2, and someone with experience
asks them to quit leaning on the rules and use their heads.

Judging from the length and intensity of this thread, however, we happily
seem quite able to think for ourselves and counteract slogan-itis.

Now, who's up for a discussion of why "predictability does not, on its own,
necessarily equal usability"?

26 May 2008 - 8:57am
Jeff Garbers
2008

On May 26, 2008, at 9:01 AM, Todd Zaki Warfel wrote:
> On May 25, 2008, at 1:23 AM, Kontra wrote:
>
>> Not everything that's usable is predictable and not everything that's
>> predictable is usable.
>
> For example?

Usable but not predictable: iPod Shuffle.
Predictable but not usable: IRS Form 1040.

26 May 2008 - 9:02am
martinpolley
2007

>
> Usable but not predictable: iPod Shuffle.

But that unpredictability is predictable :)

Martin

26 May 2008 - 11:29am
Robert Hoekman, Jr.
2005

>
> I was sitting in the front row of your closing keynote in Canberra Monday a
> week ago. You may remember me as "Donna's crazy boyfriend". And the
> comment? Basically, none of us look as good as we do in our promo shots -
> not negative, just the way it is :)
>

Ha! That's hilarious. But I think I'm insulted—that photo is only 2 years
old. :) I couldn't have aged that much!

-r-

26 May 2008 - 11:34am
Robert Hoekman, Jr.
2005

>
> Now, who's up for a discussion of why "predictability does not, on its own,
> necessarily equal usability"?
>

Me!

-r-

26 May 2008 - 2:01pm
Todd Warfel
2003

On May 26, 2008, at 9:31 AM, james horgan wrote:

> why is predicatability seen as a good or useful thing in todays
> competitive market? useable design can be both surprising and fresh,
> and people want to get on that learning curve just to try something
> new and play with a new product.
> usability is a basic part of a good design, but its the creativity
> of the design that counts.

Just because a design is predictable doesn't mean it's not new,
innovative, or creative. The iPhone and Tags example I gave are good
examples. Both are predictable, but innovative and refreshingly new.

Cheers!

Todd Zaki Warfel
President, Design Researcher
Messagefirst | Designing Information. Beautifully.
----------------------------------
Contact Info
Voice: (215) 825-7423
Email: todd at messagefirst.com
AIM: twarfel at mac.com
Blog: http://toddwarfel.com
Twitter: zakiwarfel
----------------------------------
In theory, theory and practice are the same.
In practice, they are not.

26 May 2008 - 2:04pm
Todd Warfel
2003

On May 26, 2008, at 9:57 AM, Jeff Garbers wrote:

> Usable but not predictable: iPod Shuffle.
> Predictable but not usable: IRS Form 1040.

Yes, laughingly, but admittedly true. Have you considered doing
standup as a side job :).

Cheers!

Todd Zaki Warfel
President, Design Researcher
Messagefirst | Designing Information. Beautifully.
----------------------------------
Contact Info
Voice: (215) 825-7423
Email: todd at messagefirst.com
AIM: twarfel at mac.com
Blog: http://toddwarfel.com
Twitter: zakiwarfel
----------------------------------
In theory, theory and practice are the same.
In practice, they are not.

25 May 2008 - 5:22pm
cfmdesigns
2004

Predictable isn't the same as deterministic. A slot machine is/should be completely predictable: push the button, the "wheels" spin, and a payout occurs as appropriate. Which is why I don't like video slots with 9 or 15 payout lines. Even after seeing the payout results, I can't say why something won or not.

-- Jim Drew / CFM Designs
cfmdesigns at earthlink.net

----- Original message -----
From: Robert Hoekman Jr <robert at rhjr.net

For the record, something about "usability = predictability" has bothered me
since I first saw it written yesterday. I'm playing devil's advocate here to
see if it holds up. I don't think it does. I'm relying on the IxDA community
to come up with all those crafty arguments that make it fall apart.

I tossed this out to the Twitterverse last night as well. The most practical
reply I got? Slot machines. Definitely usable while unpredictable.

27 May 2008 - 8:49am
Matt Nish-Lapidus
2007

It seems to me that what we're really talking about is
reproducibility. The first time somebody uses a computer nothing is
predictable. But as they become familiar with it everything becomes
reproducible. ... and that leads to the feeling of predictability.
I think the same could be said about most interfaces... the goal for a
first time user is to make things intuitive, so in that way i guess
you could say "predictable" ... but a lot of the time it comes out of
learned behavior and reproducible results.

On Sun, May 25, 2008 at 6:22 PM, Jim Drew <cfmdesigns at earthlink.net> wrote:
> Predictable isn't the same as deterministic. A slot machine is/should be completely predictable: push the button, the "wheels" spin, and a payout occurs as appropriate. Which is why I don't like video slots with 9 or 15 payout lines. Even after seeing the payout results, I can't say why something won or not.
>
> -- Jim Drew / CFM Designs
> cfmdesigns at earthlink.net
>
> ----- Original message -----
> From: Robert Hoekman Jr <robert at rhjr.net
>
> For the record, something about "usability = predictability" has bothered me
> since I first saw it written yesterday. I'm playing devil's advocate here to
> see if it holds up. I don't think it does. I'm relying on the IxDA community
> to come up with all those crafty arguments that make it fall apart.
>
> I tossed this out to the Twitterverse last night as well. The most practical
> reply I got? Slot machines. Definitely usable while unpredictable.
>
> ________________________________________________________________
> Welcome to the Interaction Design Association (IxDA)!
> To post to this list ....... discuss at ixda.org
> Unsubscribe ................ http://www.ixda.org/unsubscribe
> List Guidelines ............ http://www.ixda.org/guidelines
> List Help .................. http://www.ixda.org/help
>

--
Matt Nish-Lapidus
work: matt at bibliocommons.com / www.bibliocommons.com
--
personal: mattnl at gmail.com

28 May 2008 - 4:08pm
Jeff Seager
2007

Thanks for sparking an interesting discussion, Robert. I agree with
your premise, too.

Among other ideas this discussion generated in me is an analogy with
music and poetry. Predictability in meter or rhythm is desirable and
usable, but so is variation. We want the familiarity and cohesiveness
of variation on a theme, rather than random variation.

I recently ordered something from despair.com, where they've done a
great job of marketing the art of the curmudgeon. At checkout time,
everything works as expected with a perverse twist. You get a message
something like "This is where we suck the money out of your bank
account and exchange it for the useless crap you've ordered." And
you're informed about how to exchange merchandise that isn't what
you expected ("as if we care"). And so on. The functional
predictability makes for good usability, and the unpredictability of
the messages makes it fun -- and consistent with the site's theme.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Posted from the new ixda.org
http://www.ixda.org/discuss?post=29451

28 May 2008 - 10:03pm
Jared M. Spool
2003

On May 24, 2008, at 8:54 PM, Robert Hoekman Jr wrote:

> "Usability equals predictability."
>
> As in, if you can accurately predict what's going to happen next in an
> interaction, it's because the action you're taking is
> understandable, clear,
> logical, makes you feel confident, etc. If you can accurately
> predict what's
> next, the interaction has high usability. If you can't accurately
> predict
> what's next, the interaction has low usability.
>
> Shoot holes in that statement.

Usability is a scale from extreme frustration to extreme delight.

Delight, by definition, is something that is surprisingly good.

By being surprised, it has to exceed the bounds of predictability.

Therefore, Usability != predictability.

And remember: Every time you try to define usability, God kills a
kitten.

Please, remember the kittens.

Jared

29 May 2008 - 4:06pm
Robert Hoekman, Jr.
2005

> Usability is a scale from extreme frustration to extreme delight.
>
> Delight, by definition, is something that is surprisingly good.
>
> By being surprised, it has to exceed the bounds of predictability.
>
> Therefore, Usability != predictability.

Best argument yet.

And yes, I'll be sure to look out for the kittens, but I'm really more
of a patron saint of stray dogs in my neighborhood.

-r-

29 May 2008 - 4:15pm
Jeff Seager
2007

Conceptually, I can agree that usability is a continuum (or a scale,
as Jared puts it). To the extent that a definition is possible, for
the reasons Chauncey points out, I think we _must_ define it.
Otherwise we have all the credibility of the ancient alchemist,
shrouding our work in mystery and ultimately having it condemned as
hokum.

The specific components or attributes of usability do vary from one
project to another. But predictability, being partly intuitive (the
user's responsibility) and partly experiential (the
designer/programmer's responsibility), is a key attribute that moves
us toward the side of the usability continuum.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Posted from the new ixda.org
http://www.ixda.org/discuss?post=29451

29 May 2008 - 4:17pm
Jeff Seager
2007

... the above should have read:

'But predictability, being partly intuitive (the user's
responsibility) and partly experiential (the designer/programmer's
responsibility), is a key attribute that moves us toward the "plus"
side of the usability continuum.'

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Posted from the new ixda.org
http://www.ixda.org/discuss?post=29451

29 May 2008 - 4:29pm
Eugene Chen
2004

While obviously predictability is wanted most of the time, I feel like
this formulation would lead one to making more explicit (ie wordier)
and more consistent (ie conventional) designs.

The designs I admire most have neither of these qualities. The
designs I admire most tend to have a certain amount of ambiguity, but
because of a certain internal logic/aesthetic/feel - users seem
comfortable to explore them, click around, figure out a new space,
new possibilities. This kind of ambiguity is a requirement in video
games, but also can lend other applications a kind of intriguing
quality.

It's great when users trust the design to give them a good time.
Then the design doesn't have to be so defensive or try so hard to be
predictable.

Also, more and more interaction design is moving into behind the
scenes algorithms which aren't really predictable. For instance, you
can't predict the result of a search query or you wouldn't need to
do it.

Lastly, good art avoids predictability and I think there is room in
what we do for these softer qualities.

I would prefer "possible" or "probable" over "predictable".

- Eugene

Eugene Chen Design
User Experience | Strategy Research Design
http://www.eugenechendesign.com

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Posted from the new ixda.org
http://www.ixda.org/discuss?post=29451

29 May 2008 - 5:47pm
Kontra
2007

> > Delight, by definition, is something that is surprisingly good.
> > By being surprised, it has to exceed the bounds of predictability.
> Best argument yet.

Only if it were true.
I for one am delighted constantly by eating the food I like, drinking
the wine I enjoy, meeting the people I love, revisiting the places
I've been to, etc. In fact, a good part of 'delight' is the
familiarity and predictability in (re)connecting with what one knows,
rather than being surprised. Delight and predictability are in no way
mutually exclusive.

As to kittens, we already have way too many of them. :-)

--
Kontra
http://counternotions.com

29 May 2008 - 11:54pm
Gavin Burke
2008

Have been keeping an eye on this thread and was thinking of a real
world example of usability != predictabilty.

You walk up to a door way, you put out your hand to push in the door
and it opens automatically.
I had predicted that I would have to push in the door, but was nicely
surprised when it opened by itself
requiring less physical effect. At the other end of the the scale if
having reached for the door to push it in, I had to pull it out
instead...
But what if there was no door at all.

Think it comes down to having a goal or task in your head and how you
get there can be both predictable or unpredictable in good and bad ways.

On 29 May 2008, at 14:29, Eugene Chen wrote:

> While obviously predictability is wanted most of the time, I feel like
> this formulation would lead one to making more explicit (ie wordier)
> and more consistent (ie conventional) designs.
>
> The designs I admire most have neither of these qualities. The
> designs I admire most tend to have a certain amount of ambiguity.

30 May 2008 - 12:45am
Steve Baty
2009

Hmmm, this reminds of the automatic lights in the bathrooms where I'm
working currently.

2008/5/30 Gavin Burke|FAW <gavin.burke at futureaudioworkshop.com>:

>
> You walk up to a door way, you put out your hand to push in the door and it
> opens automatically.
> I had predicted that I would have to push in the door, but was nicely
> surprised when it opened by itself
> requiring less physical effect. At the other end of the the scale if having
> reached for the door to push it in, I had to pull it out instead...

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