Consider this: You’re in a meeting where interpreting Cost Variance needs to be done and done fast!. You look at your project dashboard and see a number labelled ‘Cost Variance’ and it’s negative. The stakeholders are all looking at you expectantly, and suddenly you can’t quite remember what this common earned value metric is all about.
Fortunately, interpreting Cost Variance doesn’t require a finance degree. We’ve got a detailed article explaining what CV means in project management, so in this article we want to go further. We’ll talk about what it tells you about your project and what to do if the number looks alarming.
Interpreting Cost Variance
As a reminder, Cost Variance (CV) = Earned Value (EV) – Actual Cost (AC). CV is simply about comparing the value of what’s been done (EV) to what’s actually been spent (AC).
If the number is positive, it means you are under budget. A negative CV shows that you are over budget, and if the number is zero, your project is performing exactly as you had forecasted – well done! (Although we’d be surprised if that position was maintained for the whole project.)
CV is one of the key EVM metrics, often used alongside Schedule Performance Index (SPI), Cost Performance Index (CPI) and others. It’s typically used as part of a suite of metrics to give you a balanced, data-driven view of project performance. Together, CV and CPI show the cost efficiency of the project and help with forecasting estimate at completion – the final cost for a project.
Why CV matters
The CV metric helps you track project financial performance, spot budget overruns early and report clearly to sponsors and stakeholders.
Once you’re confident, you’ll find you use it forecasting final costs and making data-driven decisions like how to reallocate resources, whether to freeze spend, or whether to get into renegotiating contracts.
Positive Cost Variance: should you celebrate?
Let’s say that your CV is $80,000. That’s good news, right? You’ve spent less than you expected to at this point in the work, so you must be doing a great job.
Well, that’s only true if you really have earned the value you were expecting. Perhaps EV was overestimated. Perhaps the project is running behind so there hasn’t been the need to spend the money yet. Perhaps the supplier has billed late, or come to an agreement with the account manager to bill at a different time to the original contract terms.
Resources could be under-spending but also under-delivering, so check into the quality of the output. A positive CV is only good if the earned value is accurate and sustainable, and you’re happy with what’s being delivered.
How to respond to a negative CV
If your Cost Variance is negative, you are going to be asked how that happened and what you are doing about it. Here’s a structured way that you could respond:
- Step 1: Confirm the data is accurate (especially actual cost and EV inputs)
- Step 2: Diagnose: Where is the overrun coming from?
- Step 3: Engage with work package owners or CAMs
- Step 4: Look for corrective actions. These could include stopping spend in certain areas, replanning resources to do work later in the project, negotiating with vendors or requesting to spend the management reserve or risk budget if that can be justified.
However, if this is the first month you’ve been negative, then it’s probably relatively easy to identify the cause and take steps to course correct. It doesn’t mean that the whole project is in danger, but it’s a useful warning. Trends matter more than a single month’s data, so focus on getting back on track as quickly as you can.
Common causes of negative Cost Variance
There are lots of reasons why CV could be negative. For example:
- Labor cost overruns: Did the team work extra hours or unplanned overtime?
- Rework or scope creep: Did you have to do extra work that wasn’t reflected in the earned value metrics?
- Expensive resources: Did you rely more heavily on the most expensive suppliers or resources than expected?
- Poor estimating: Was the baseline poorly calculated, so the actuals aren’t aligning?
- Poor time tracking: Do you really know how many hours were worked against which task?
- Inefficient processes: Has it taken longer to complete tasks than expected due to poor processes?
Dig out timesheets, status updates, risk reports and performance logs to see if the root cause jumps out at you.
Reporting CV to stakeholders
As a rule of thumb, sponsors (and the people paying for the project) care more about CV trends than one-off values. When you’re interpreting the Cost Variance and communicating the metric, do so in the context of changes or trends from the last month, and forecasts for the future.
You should also avoid technical jargon. In our experience non-project managers find the word ‘value’ particularly tricky to get their heads around: “We’ve spent $10k more than the value we’ve earned.” You’ll get questions around what value means and how it’s calculated, so try to frame it with the impact: “This puts us 6% over budget to date.”
Always include a reason and a next step. For example, say that you are investigating the cause and will share a recovery plan in the next meeting. Always keep it factual – there’s no need to be defensive. The facts are the facts, and stakeholders should be able to support your recover plans.
CV is one of the most useful EVM metrics, but it only makes sense in context. Use it as a way to start a conversation and to prompt good questions. Whether your CV is positive or negative, it’s just information. What matters is what you do with it and where you take the project from here.