How much is too much? (Take II)

Subject: How much is too much? (Take II)
From: Geoff Hart <Geoff-H -at- MTL -dot- FERIC -dot- CA>
To: "Techwr-L (E-mail)" <TECHWR-L -at- lists -dot- raycomm -dot- com>
Date: Tue, 15 Feb 2000 12:43:13 -0500

Steve Jong observes <<Geoff Hart <Geoff-H -at- MTL -dot- FERIC -dot- CA> points out that
Miller's "magic number" 7+/-2 was not based on procedure lengths. However,
from that fact it does not follow that the principle does NOT apply to
procedure lengths. It very well may. In fact, I tend to recommend 7+/-2
steps in procedures, but for some different reasons.>>

That's not quite what I said. Quoth I: "Miller's work _doesn't_ apply to
procedures composed of series of numbered steps (or at least not in this
simplistic a manner)." That is, you can certainly have more than 7 steps,
but there may be aspects of the steps themselves or the groupings of steps
that do indeed reflect Miller's observations.

Steve continued: <<The psychological principle of closure says that we want
to complete things, and can feel anxious when that completion is delayed or

This is at least in part the basis for my comment that "...if I encounter a
huge list of steps, I'm very strongly motivated
to break it up into smaller chunks just to ensure that the procedure doesn't
seem so intimidating... Most long procedures can easily be broken up into
subtasks, with "take a break and wipe your forehead; it's safe to stop for a
moment" positions midway along the way." "

Steve provided a further example: <<The definition could easily run 200-250
characters, entered in line mode--that is, once you entered a line you
couldn't edit it. In training, even expert users, given a list of rules to
type exactly as shown, were completely unable to type that long a line
without errors; and then they had to enter the whole thing again. The
problem wasn't just the primitive interface or the questionable typing
skills of the user; it was also performance anxiety as the commands got
longer and longer and longer...>>

Which is why you need to work with both the users and the interface
designers to adopt a solution that fits everyone's needs. In this case,
chunking might help, but the real solution is to get the designers to let
you input the information in smaller, more easily edited groupings (e.g.,
via a dialog box with checkboxes and drop-down menus or a series of prompts
in which users enter one subset of the larger command at a time). Even a
skilled typist, with a 1% error rate, is going to average 2.5 errors on a
250-character command; regular typists would do far worse. It's incompetent
interface design to ignore this kind of consideration and require perfection
from the users.

<<Limiting procedures to seven steps helps keep to the correct level of
detail. If you have a 40-step procedure, are the steps really too small for
the target audience? Maybe you're trying to direct experienced system
administrators to move the mouse to the File menu, to click once, to pull
the mouse down to the Open... item, to click again, to... (AARGH!)>>

That's a good point, but it's hard to apply this rule broadly. Setting your
preferences in Word shouldn't take more than a 7-step procedure, but running
through the troubleshooting checklist for part of a complex device with
multiple failure modes could easily run to 40 steps or more. I'd suggest
that Steve's entirely correct for the relatively simple things most of us
document most of the time, but there can be dramatic exceptions.

<<Finally, the seven-step guideline is a sanity check on the product itself.
If it really takes 40 steps to accomplish something, one can argue the
product is inherently too complex.>>

Amen. See my previous techwr-l posting on the cryptography problem for an
example of alternatives to inherently complex procedures.

--Geoff Hart, Pointe-Claire, Quebec
geoff-h -at- mtl -dot- feric -dot- ca
"The paperless office will arrive when the paperless toilet
arrives."--Matthew Stevens

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