"Manifesto for Agile Software Development"- Common values and principles

"... we have come to value:

    Individuals and interactions over processes and tools

• Tools should adapt to allow individuals to produce better work

    Working software over comprehensive documentation

• Less a knock on documentation

• More a goal for clearly named and written software components

    Customer collaboration over contract negotiation

    Responding to change over following a plan"

• Plan should adapt or change to fit current needs

• Process should be adaptive

Iterative development seems to be common basis for virtually all models