The whole-team approach, also called the team-based approach, is a style of project management in which everyone on the project team is held equally responsible for the quality and success of the project. The term is often used in agile software development, lean production and creative teams in advertising and other media.
A whole team approach recognizes that in order for the team to be successful, members cannot operate in isolation. Each team member must know and appreciate every other team member's strengths and skills. Each team member must also be willing to switch roles when the need arises and remained focused on the success of the project, doing whatever is necessary whether or not it's technically "their job."
In agile development, this means that everyone on the development team is equally responsible for quality. In the book, “Agile Testing – A Practical Guide for Testers and Agile Teams,” by Lisa Crispin and Janet Gregory, the whole-team approach is described this way:
“ The focus of agile development is producing high-quality software in a time frame that maximizes its value to the business. This is the job of the whole team, not just testers or designated quality assurance professionals. Everyone on an agile team gets “test-infected.” Tests, from the unit level on up, drive the coding, help the team learn how the application should work, and let us know when we’re 'done' with a task or story.”