Ví dụ: ". xem đám mây bão của radar ." Xác định các tiêu chí kiểm chứng Mỗi yêu cầu phải được kiểm chứng. Thường thì bạn có thể chỉ ra một bài kiểm tra có thể bằng cách thêm một cụm từ đơn giản để hội đủ điều kiện một nhu cầu cơ bản. | Writing Better Requirement 69 Example .view storm clouds by radar . Define verifiable criteria Every requirement must be verifiable. Often you can indicate a possible test by adding a simple phrase to qualify a basic need. Later you will connect a specific acceptance criterion with the requirement text. Example . at least WO kilometers ahead Acceptance criterion Aircraft flying at 800 km hour at 10 000 meters towards a known storm cloud indicated by meteorology satellite report storm cloud is detected at a range of at least 100 km. You do not necessarily have to write acceptance test criteria while you are preparing user requirements but you should be sure that practical tests or other ways of verifying your requirements can be devised readily. If it isn t verifiable it isn t a requirement. Suzanne Robertson talks in slightly different language about fit criteria - how well a solution fits the requirement system designers can use the criteria to satisfy themselves that they have found a solution acceptable to users Robertson 1999 . In Robertson s method every requirement contains not only a textual description of the user s intention but also a fit criterion. This strict approach means more effort while writing but promises fewer problems later in the project. User requirements may be clear but hard to verify. For example The crew find the sailboat fun to sail could in principle be tested in a series of trials using representative volunteers of different ages and levels of experience. The acceptance criterion might be that the average enjoyment score is over 50 . This is a feasible approach and though it might be costly in practice testing is usually cheaper than making a product that does not attract users. Don t write like this There are many ways of losing control of a project through bad requirements. Here are some things to avoid. None of the rules are absolute - you can probably make up examples where each of the danger signs is reasonable in a .