Believing What You're Told

One of the biggest challenges I've experienced in data warehousing is that analysis has to take place from three sometimes very divergent and contradictory perspectives:

• How does your user perceive the nature of the business?
• How do users of the source systems perceive their own activities?
• How do source systems record the activities of their users?

I've run into many times where there are various degrees of disagreement between those three perspectives.  It's the challenge of a good analyst to get to the bottom of these discrepancies, understand why perceptions are what they are, and be able to believe that there is complete truth in each of them... even if the source system only says one thing.

Sometimes even harder than the philosophical challenge of reconciling those divergent perspectives is the act of reconciling them into a common model of understanding in the form of a reporting system or data warehouse.  Woe to any architect or modeler who takes one of the stories as gospel and disregards the others.

#pragprowrimo word count: 12,005