Leavadial

A leavadial is a concept in requirements analysis and traceability, where the designer does not have ample requirements data to determine the appropriate default value (computer science) of a variable. The designer decides to arbitrarily set the value, and then provide a method (computer science) for changing the default value. It could be said that the designer is "leaving a dial" in the design, so that users or future maintainers of the system will be able to adjust the value to meet their needs.

Leavadials present a problem in the Verification and Validation (V&V) phase of a project, as they are not the result of requirements for customization, but rather a result of missing requirements for what the value should be.

Leavadials are sometimes referenced as evidence of weaknesses in the Waterfall model of software development, and used as examples when comparing Waterfall to an alternative software development model.