The investments needed to bring a software project to the market are substantial and can extend over several years. Managing software development requires not only technical expertise, but communication with funders and economists. This paper presents methods to estimate a parameter which captures the effective investment time, lag. The lag parameter is useful in assessing progress towards the goal of having a quality product, while scheduling resources, assessing the risk, considering options, capitalization of investments, and predicting taxation consequences. The paper presents the lag estimation methods for a new product, for additional versions of a product, and for complete product replacement.

lag, software development, investment