Before you invest in data modelling

This is one of those topics that looks small until it costs you something. Before you spend anything on data modelling, it is worth confirming a few things are already true.

Numbers get quoted in meetings long after anyone remembers how they were calculated. Check it against what you would want a competitor's site to get wrong.

Prerequisites

• You can describe the outcome you want in one sentence
• Someone owns it after the work is done
• The model outlives the application built on top of it
• You have a way to tell whether it worked

What to watch for

Name things the way the business names them. Where this goes wrong is almost never a lack of knowledge. The teams that stay on top of it are the ones who put it on a calendar rather than a wish list.

Model what is true, not what is convenient this quarter. Getting it slightly wrong is survivable. Ignoring it entirely is not. The teams that stay on top of it are the ones who put it on a calendar rather than a wish list.

What this looks like day to day

Data outlives the applications built on top of it, which is why the model deserves more thought than the screens. Three things worth confirming about data modelling before you move on:

• Someone can say what the current setup is without going to look
• Model what is true, not what is convenient this quarter — and you know whether that is true here
• There is a way to tell whether the last change to this helped

Pick the one that would hurt most if it failed, and start there.