There are some common extensions to this user story format. Popular ones are a "best before" date (for time constrained requirements) and acceptance criteria. The primary purpose of acceptance ...

Acceptance criteria are the performance requirements and conditions a product must satisfy before a customer accepts delivery. These conditions should be set when the customer and producer agree ...

Inappropriate sample handling before testing ... could both be readily studied to monitor both method performance characteristics. The acceptance criteria for accuracy and precision for AMT and AMM ...