A sidewalk-heave team fitted on last winter’s shed photos. Spring heave on wet brick is the live job. How should representativeness be defined?

Last winter’s shed photos are an available archive. Spring heave on wet brick is the live job. Representativeness is how closely train, validation, and test match that operational data, not how closely they match the shed pile. Archive-only matching, a Chapter 6 drift-test method, and a range constraint miss that definition.