This Guest paper was originally published in 2008.*
With some updating of the text, it is reproduced here with the permission of the author.
Copyright Joe Marasco © 2015. Published here September 2015.

* See The UMAP Journal 24 (4) (2004) 357-374 for a more detailed discussion.

Editor's Note | Introduction | Model Assumptions


Project managers often have a hard choice to make: Adding new employees can help them get to the finish line faster, but in the short term they drag down the existing team, because the pros take time to help them during ramp-up. Is the time-to-market advantage worth the increased cost?

In this paper we work through a sample problem illustrating the tradeoff, and provide a tool to enable you to make similar calculations based on the parameters for your organization.

Sample case in point

You have an existing team that is 100% productive and can complete the current project in one year at current staff levels. Management would like to complete the project in ten months by adding new hires. Most likely this request comes because the project is two months behind its original intended completion date, and management would like to hold to that date.

How many people do you have to add, and what will be your increase in cost, if the new people are productive at only 60% due to their ramp-up, and the organization has a drag factor of 0.5? Drag is the number of hours of existing team time consumed for each hour of non-productive new hire time. That non-productive time is spent learning and making mistakes. The existing team has to take time to do the teaching, and finding and correcting the mistakes. All other things being equal, organizations with good documentation will have a lower D than organizations with little or poor documentation.

The solution to this problem requires the use of Joe's Answergraph™ illustrated below, but also available as a download. See below for more details underlying the nomogram.


We need 20% more useful hours in order to get 12 months work done in ten months. Using the Answergraph™ shown below, with P = 0.6 and D = 0.5, we find a value for M of 0.4. Then with a ΔH = 20% and time = 10 months, we find that G = 50%, meaning that we need to grow the team by half.

The overall productivity during the 10 months is 80% of its previous value, and the cost to complete the project will go up by 25%.

Figure 1: Joe's Answergraph
Figure 1: Joe's Answergraph™
(For a full size 8.5"x11" download, press HERE.)
Editor's Note  Editor's Note

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