Re: How much is too much?

[SteveFJong -at- aol -dot- com]

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.

As the saying goes, when you're up to your butt in alligators, it's hard to 
remember you went in to drain the swamp. The psychological principle of 
closure says that we want to complete things, and can feel anxious when that 
completion is delayed or denied. Think of the tension of songs that end "one 
note early," or Roger Rabbit's inability to resist the "shave and-a-haircut" 
knock. ("TWO BITS!" he screamed, completing the phrase but revealing himself 
to Judge Doom...)

But enough silly examples. I worked on a network management application, one 
module of which had a command-line interface. You could define alarms on 
network entities by entering a definition. 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...

As Lisa Higgins <LHiggins -at- carrieraccess -dot- com> points out, the goal of a 
procedure is not to memorize it. Yet you need to remember how far along you 
are. If you're in step 23 of 40, you can easily lose your place, and I'd 
claim it's because of short-term-memory overload.

There are more practical considerations. 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!)

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. Without checkpoints, the chances of an error 
obviously increase with procedure length. (My gut tells me this is a 
persuasive argument!)

          -- Steve

Steven Jong, Documentation Team Manager ("Typo?  What tpyo?")
Lightbridge, Inc., 67 S. Bedford St., Burlington, MA 01803 USA
mailto:Jong -at- lightbridge -dot- com   781.359.4902[V], 781.359.4500[F]
Home Sweet Homepage: http://members.aol.com/SteveFJong