The hourglass model is an approach to layered system architecture where a middle layer is intentionally constricted in order to support flexibility in the implementation of layers above and below.

Against what bases are queries against your data evaluated? If you only expose a single “data base” that changes over time, then data citations cannot be a combination of query and basis.

Many tests use oracles, where you know the answers for some inputs and you check those correspondences.

In a collaboration, data objects are produced at many sites. To make the data objects findable, you may steward a central, searchable index for their metadata.