Data vs Decision Science

Brought up in DataScienceCentral:  What is the difference?  I support making sure we include the people that understand the decision processes involved as early as possible. Else how do we hope to understand the implications in changes we are proposing?  I am not sure this is 'science' in any sense, but it is at very least having access to decisions as they are made today.   Start at the level of Business Process Modeling, which covers the same space.