Tuesday, October 29, 2013

Data Item Description

In  the old days (in the last century) -- in the defense and the aerospace domains -- we used to routinely write "data item descriptions" (DiD) to define or explain what we meant by a particular data item.

Example: Define "customer" as a data item that might appear in a database. This is no small matter if you've ever tried to do it. You have the buyer, the decision maker, the user, the payer, and the warehouse receiver, to name some but not all. There are also physical descriptions, as in the headquarters, the sales office, the warehouse, etc.

So, it came to pass recently that I was on a volunteer project whereon there was a security task: we were asked to be on the lookout for "bags" and not let them pass a certain gate.

Indeed: what is a 'bag'? Like "customer" this is no small matter to define, and no one on the project wrote a DiD, and likely could not have if asked.  A lost skill? Perhaps!

And so, there were plastic bags, hand bags, back-packs, fanny packs, hyropaks, arm totes -- really, what is a bag?

A classic case of "where you stand depends on where you sit". If you are on a security task, everything looks like a bag! Otherwise, why is a fanny pack a bag?

Suffice to say: there is nothing like a DiD when trying to communicate clearly
Part 1: tell them what you are going to tell them
Part 2: tell them
Part 3: tell them what you told them.

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