Get Ready for Agile Methods, with Care

F aced with the conflicting pressures of accelerated product development and users who demand that increasingly vital systems be made ever more dependable, software development has been thrown into turmoil. Traditionalists advocate using extensive planning, codified processes, and rigorous reuse to make development an efficient and predictable activity that gradually matures toward perfection. Meanwhile, a new generation of developers cites the crushing weight of corporate bureaucracy, the rapid pace of information technology change, and the dehumanizing effects of detailed plan-driven development as cause for revolution. In their rallying cry, the Manifesto for Agile Software Development (http://www.agileAlliance.org), and in columns such as those the “Ongoing Debate” sidebar describes, these developers call for a revitalized approach to development that dispenses with all but the essentials. Unsurprisingly, many developers who favor plan-driven methods have reacted to the manifesto with scathing criticism. Real-world examples argue for and against agile methods. Responding to change has been cited as the critical technical success factor in the Internet browser battle between Microsoft and Netscape. But overresponding to change has been cited as the source of many software disasters, such as the $3 billion overrun of the US Federal Aviation Administration’s Advanced Automation System for national air traffic control. I believe that both agile and plan-driven approaches have a responsible center and overinterpreting radical fringes. Although each approach has a home ground of project characteristics within which it performs very well, and much better than the other, outside each approach’s home ground, a combined approach is feasible and preferable.