When to Recommend Against Using an Agile Method

(1) The system is safety-critical and requires complete upfront analysis of all requirements to check for interactions that may compromise safety or security

(2) The system must be approved by an external regulator, such as a certification authority, which requires detailed documentation as part of the safety case

(3) The development team is large and distributed, making the informal communication that agile depends on impractical

(4) The organisation has bureaucratic quality procedures and standards that are incompatible with agile's informal, documentation-light approach

(5) The requirements are well understood and unlikely to change, making an incremental discovery approach unnecessary

(6) The customer is unable or unwilling to be closely involved throughout the development process

Explanation

Agile is not recommended when: the system is safety-critical and needs complete requirements analysis for safety/security interaction checking; external regulation requires detailed documentation; the team is large and distributed, making informal communication impractical; organisational quality standards are incompatible with agile; requirements are stable and well understood, making plan-driven approaches more efficient; or the customer cannot be closely involved, making the customer involvement principle impossible to realise.