km3 Contract Deliverable Item Description (CDID) hri07e
11.0 Data Typing
In a large project requiring several dozen (or several hundred) “deliverables” there is a tendency for the same “data elements” to be called for over and over again – and tendency to give localized names for what is essentially the same variable. This results in a much larger number of variables than are “canonical” for the project and also results in the same data element having different values in different deliverables. Perhaps the most extreme result is that it may be possible in the feedback loop between deliverables to cause the various estimates of the data element to diverge – rather than converge – as attempts are made to update the variable from various sources. (For example: an airplane is a balancing act between structural integrity, carrying capacity, range and so on. Everybody involved needs to know what the plane “weighs” in various configurations rather precisely and the surprise weight changes can be very costly.)
It behooves every author of a CDID to avoid creating new data elements for elements that may already be defined elsewhere and will need to be reconciled and communicated to other members of the project team. The Data Dictionary is a human readable control document that can do that and which can be more easily automated into XML or similar data languages used to coordinate the information flow. As much as possible the Data Dictionary from one project should contain the same definitions as the next project and if achieved will avoid many common project start-up crises and allow more confidence in the definitions themselves after they have been successfully applied for multiple projects.