The MoSCoW method is a prioritization technique used in management, business analysis, project management, and software development to reach a common understanding with stakeholders on the importance they place on the delivery of each requirement; it is also known as MoSCoW prioritization or MoSCoW analysis. The term MOSCOW itself is an acronym derived from the first letter of each of four prioritization categories: M - Must have, S - Should have, C - Could have, W - Won't have. The interstitial Os are added to make the word pronounceable. While the Os are usually in lower-case to indicate that they do not stand for anything, the all-capitals MOSCOW is also used. Background This prioritization method was developed by Dai Clegg in 1994 for use in rapid application development (RAD). It was first used extensively with the dynamic systems development method (DSDM) from 2002. MoSCoW is often used with timeboxing, where a deadline is fixed so that the focus must be on the most important requirements, and is commonly used in agile software development approaches such as Scrum, rapid application development (RAD), and DSDM. Prioritization of requirements All requirements are important, however to deliver the greatest and most immediate business benefits early the requirements must be prioritized. Developers will initially try to deliver all the Must have, Should have and Could have requirements but the Should and Could requirements will be the first to be removed if the delivery timescale looks threatened. The plain English meaning of the prioritization categories has value in getting customers to better understand the impact of setting a priority, compared to alternatives like High, Medium and Low. The categories are typically understood as: Must have Requirements labelled as Must have are critical to the current delivery timebox in order for it to be a success. If even one Must have requirement is not included, the project delivery should be considered a failure (note: requirements can be downgraded from Must have, by agreement with all relevant stakeholders; for example, when new requirements are deemed more important). MUST can also be considered an acronym for the Minimum Usable Subset. Should have Requirements labelled as Should have are important but not necessary for delivery in the current delivery timebox. While Should have requirements can be as important as Must have, they are often not as time-critical or there may be another way to satisfy the requirement so that it