想定

1. Origins, structure, and basic meaning

• Structure: 想定 (そうてい) is an action noun for assuming a possible future situation or the range anticipated.
• Basic usage: 停電を想定して用意する assumes a power failure for preparation, while 当初の想定を超える says actual attendance exceeds the original forecast.

2. Common pitfalls and similar expressions

• Assumed event and forecast range
  • 停電を想定する places an event in a scenario, whereas 想定を超える exceeds a forecast boundary. It does not say the power failure actually occurred.