What's Changed
What's changed is a subset of what's new. And what's new is a subset of what's changed.
It is all a matter of timing and this what makes information management so challenging for organizations.
Sometimes, you can start with a clean slate but other times you are working with existing information.
Updating existing information is often more difficult than adding new information -- especially when information is synching from multiple source.
Newer information is not necessary better or more accurate than older data. Recency is only factor for validating information.
For data to be accurate and valid, you really need to pay attention to a lot of variables that all make a difference.
The interpretation of data is anything but definitive.