Why model data fails
The common failure is not missing data. It is inconsistent data: the same property named three different ways across three disciplines, or populated thoroughly in one model region and left blank in another because a different team modelled it.
Inconsistency is worse than absence, because absence is obvious and inconsistency looks like completeness until somebody tries to export the asset register.
The four checks
Completeness
Does every object of a given type carry the properties the employer's information requirements actually ask for?
Consistency
Are property names, units and value formats identical across disciplines and across every federated model?
Classification
Is every object mapped to the agreed system, and mapped at the correct level of its hierarchy rather than the broadest available code?
Validity
Do values sit inside plausible ranges? Fire ratings of zero and negative areas are common, and trivially catchable automatically.
When to run them
Validation applied only at handover finds problems at the point they are most expensive to fix. The identical checks run at each model issue cost a fraction to resolve, because the person who created the error is still on the project and still remembers the decision.
Automated rule checking handles completeness and format well. It handles intent poorly. Whether the right object was classified as the right thing still needs somebody who understands the design to look at it.
The verification that cannot be automated
Every validation regime eventually reaches a check that requires someone on site with a clipboard. Confirming that the plant installed matches the plant specified is not a rule you can write, and it is the check that most often changes the handover data.
That keeps a surprising amount of travel in the schedule. For teams working Florida projects, the arrival is usually a booked taxi out of Miami International rather than a rental; port and marine assets pull people toward Port Everglades instead, and north-county sites make the Boca Raton transfer the practical one to hold in the calendar.