Variance At Completion (VAC) is the difference between what the project was originally expected (baselined) to cost, versus what it is now expected to cost.
Every month, our vendor is required to report this total on the project as a whole and on key deliverables. I’m used to seeing the numbers reported and how to calculate them. I’m not asking for the Cost Performance Index (CPI). I want to know how far over or under we’re going to be compared to the budget.
The formula I memorized for the PMP exam and the same formula I use to calculate VAC today is: Variance At Completion = Budget At Completion – Estimate At Completion
(VAC = BAC – EAC)
So, I ask myself, [1] why is there no VAC definition and [2] VAC formula in the PMBoK?
The number one search on the Critical Path website is for a Critical Path and Float worksheet. Though you should be using software to calculate a critical path, if it is mission critical, it is important to understand the concept for the PMP exam.
Rather then go into the specifics on how to calculate the critical path and float in this post, I’ll merely say a free worksheet template and PowerPoint presentation are available and you can download them at any time. (see links below)
•Remember the Critical Path tells you the activities that can not slip a day without increasing the total duration of the project or moving the project completion date. It is the longest path of logically related activities through the network which cannot slip without impacting the total project duration, termed zero float.
[Click here to download the Critical Path and Float Calculation Worksheet]
[Click here to download the Critical Path Scheduling PowerPoint Presentation]
Also available in PDF
General | Derek Huether | July 21, 2009 | 
Comments (3)
CPM, Critical Path Method, Definition, EVM, Float, Free, PMP, PowerPoint, Presentation, Project Management, Schedule, Template, Worksheet
I’ve had a subscription to a trade rag called CrossTalk (The Journal of Defense Software Engineering) for a few years now. I’ve read the articles but none really got my attention and kept it. In the December 2008 issue, there is an article about comparing Earned Value Management Methods to Earned Schedule. It was written by Walt Lipke of the Oklahoma City Chapter of PMI.
Now that I’m working on a very large government project, this article really sparked my interest. If you’re working in a government PMO or on a government project, I recommend you give it a read. The author did a really good job of using real project data and also did an excellent job comparing EVM methods to the Earned Schedule (ES) prediction technique.
If you’re new to Earned Value Management or still studying for your PMP, this may make your head hurt a little. If PVcum, EVcum, and BAC are in your daily vocabulary, you’ll enjoy it. Article Link
Should all projects or programs utilize Earned Value Management?
Short answer: No
Long answer: The industry standard for project control systems described in American National Standards Institute (ANSI) EIA-748, Earned Value Management Systems, must be implemented on all projects with a total project cost (TPC) greater than $20M for control of project performance during the project execution phase.
Earned Value Management (EVM) is a systematic approach to the integration and measurement of cost, schedule, and technical (scope) accomplishments on a project or task. It provides both the contractee and contractor(s) the ability to objectively examine detailed schedule information, critical program and technical milestones, and cost data.
In layman’s terms, it quantifies the estimated value of the work actually accomplished.
While I was doing some research for my book, I came across an excellent quote by Bill Hewlett. Do you think your boss understands this quote?
“You cannot manage what you cannot measure…and what gets measured gets done.”
— Bill Hewlett, Hewlett Packard
