Managing a Portfolio of Product Development Projects under Resource Constraints

Abstract

Managers of product development (PD) project portfolios face difficult decisions in allocating limited resources to minimize project or portfolio delay. Although PD projects are highly iterative (cyclical), almost all of the vast literature on project scheduling assumes that projects are acyclical. This article addresses this gap with a comprehensive analysis of 31 priority rules (PRs) on 18,480 portfolios containing 55,440 iterative projects. We find that the best PRs for iterative project portfolios differ significantly from those for acyclical ones, and that the best PRs at the project level differ from those at the portfolio level. The best PR depends on project and portfolio characteristics such as network density, iteration intensity, resource loading profile, and amount of resource contention. In particular, by amplifying the effects of iteration, high‐density networks hold dramatically different implications for iterative projects. Moreover, the best PR also differs depending on whether the objective is to minimize the average delay to all projects or to minimize delay to the overall portfolio. Thus, a project or portfolio manager who uses the same PR on all occasions will exhibit unnecessarily poor performance in most cases.

Optimizing Resource Allocation in a Portfolio of Projects Related to Technology Infusion Using Heuristic and Meta-Heuristic Methods

“…Studies have shown that the most suitable priority rules for iterative project portfolios differ significantly from those portfolios in which projects are acyclical [Browning and Yassine, 2015]. In this research, the performance of the 20 different priority rules used for acyclical projects are compared in the case of iterative-activity projects and 11 new rules were added that account for some characteristics of iterative projects.…”

“…In order to solve the RCMPSP, PRs remain a popular method mainly for their speed and simplicity [Vazquez et al, 2013] and because of the following reasons stated in [Browning and Yassine, 2015]:…”

“…Any miss-categorization can make the result vary widely, which is even more noticeable in [Browning and Yassine, 2015] where PRs are studied for a portfolio of iterative projects. Moreover, project characteristics have an important impact on the performance of different PRs when diverse performance objectives are considered [Patterson, 1976].…”

“…On the other hand, in [Browning and Yassine, 2010a] and [Browning and Yassine, 2015] many PRs are analyzed and explained. For the basic and improved methods, I am going to use many of the PRs covered in the mentioned researches while complementing them with others included in [Mitsuyuki et al, 2014] and [Wang et al, 2015].…”

“…In the literature review there are some works that consider iterative activities in the case of RCPSP [Meier et al, 2016] [Chen and Ju, 2010] [Luh et al, 1999] as well as the RCMPSP [Browning and Yassine, 2015], even though the literature is mostly devoid of studies that consider the multi-project problem with iterative tasks. New PRs will be considered based on the research made by [Browning and Yassine, 2015] where they studied 11 new priority rules that account for some basic characteristics of iterative projects. Finally, system dynamic models show how work intensity and overtime affect the amount of rework [Lyneis and Ford, 2007].…”