The design can be considered as an hierarchy of information, going from overall through to detail.
Eventually that detail includes information and drawings for the production of parts.
Each level of the hierarchy is composed of configuration items, each of which are specified along with their inherent limits, properties and tolerances.
These are completed in the general sequence of overall to detail, with the work on each succeeding (child) level serving to prove its parent. However, any change in the child does not necessitate a change in the parent provided that it is within the allocated tolerances.
Thus the overall quality can be improved, and rework reduced, at the cost of improved organisation.