Final answer:
The flexibility of a diaphragm in structural engineering is a measure of its ability to bend or move laterally compared to the average story drift. The exact factor that determines if a diaphragm is considered flexible depends on specific design codes, which the question does not provide.
Step-by-step explanation:
The diaphragm in structural engineering is a horizontal component, such as a floor or roof system, that is designed to resist lateral forces, typically due to wind or seismic activity. It acts as a stiff plate to transfer these loads to the building's vertical resisting elements. The question appears to be asking for a specific code or design requirement related to the flexibility of a diaphragm, which is usually determined by comparing the diaphragm's maximum lateral deformation to the average story drift.
However, without the specific reference to a design code (like the International Building Code or ASCE 7), this question cannot be answered definitively. Typically, a diaphragm is considered flexible if its lateral deformation is significantly higher than the story drift, indicating that it can bend or move more than the connected stories. The exact factor ('more than ___ the average story drift') varies according to the code and design practices being followed.