Completing projects according to plans: an earned-value improvement index

To finish in accordance with its originally planned duration or cost, a project that is not meeting its schedule or budget requires improved performance in the work that remains. This paper shows how to calculate the new productivity in terms of the average earned-value performance over the first part of a project, and it shows how the new productivity rate depends on the fraction of tasks completed. The completed task fraction beyond which recovery is impossible is calculated, and a point beyond which recovery is highly unlikely is suggested. Using an analytic approximation for an S-curve, these calculations are transformed into a temporal domain.