Lean Development and the Predictability Paradox

by Mary Poppendieck

Wall Street has little sympathy for companies unable to meet their financial forecasts each quarter. In turn, senior management expects department managers to make and meet projected goals. By the time these expectations arrive at an IT department, however, fulfilling forecasts often becomes a significant challenge. It seems that a large fraction of software projects fail to deliver on their promises for one reason or another. ¹ All too often, projects are late or over budget, or they deliver the wrong system -- or fail by all three means. Why is it that software development projects suffer from such difficulty in delivering predictable outcomes? How can the predictability of software development outcomes be more on target? This Executive Report discusses the dilemma: in our zeal to improve the reliability of software development, we have institutionalized practices that decrease, rather than increase, the predictability of outcomes.