Understanding where data comes from - which systems it goes through, which business rules have been applied and at which point in it's journey - is critical to improving and maintaining data quality and governance. In large organisations data can often pass through multiple systems before it reaches a data mart used by the business.
I've seen a rise in Bottom up data mapping exercises being conducted, particularly within data-intense departmental processes. The below thoughts discuss this type of exercise.
"You don't know where you're going until you know where you've been" (Unknown)
In order to truly understand data, and whether it is fit for our purpose we need to understand where that data has come from. Not only the system it has come from, but also what has happened to this data along the way.
"The cause is hidden, but the result is known" (Ovid)
When the result is a data quality issue, we seek to identify the root cause of this issue. This can often be a time consuming process. However, by understanding where our data has been, and what has happened at each point of our journey, we speed up the analysis process required to identify the root cause.
"The landscape should belong to the people who see it all the time" (Le Roi Jones)
By understanding where data has been we can gain knowledge of systems it has passed through, and points where it was been 'touched'. The owners of these systems (or processes) should take ownership and responsibility for the data until they pass it along to the next system.
"I'm tired of chasing people" (Robert F Kennedy)
By defining owners we can reduce the amount of time spent chasing for answers. In many organisations there is a common situation where we have a data issue but don't know who to contact about it. We call a help desk and our issue gets passed around to 5 different people. A week later it's still not resolved.
A data mapping exercise can help improve (proactive) communication in two ways. Firstly end users will understand where their data has come from. Therefore they will know who to contact directly if an issue occurs - the owner we discussed previously. Secondly, if the owner knows who they are passing data to, they can alert that person of any known issues prior to passing the issue on.