Itchy for earned value

This blog was started by me to explore ways to make Earned Valu Management (EVM), work with Critical Chain project management. It is still a worthwhile goal. I have been working hard on EVM in recent months and am now ready to get back into it. Because I am familiar with the theory behind buffer management and Critical Chain, I will focus on EVM for a while and then attempt to meld Simple EVM into the terms used by Joel Koppleman or Quentin Flemming in Critical Chain.
EVM is at its core a method to measure performance in terms cost, schedule and technical performance. EVM is a way to identify early on whether a project is at high risk. This is one of the main benefits I have heard repeatedly. Quentin Flemming stated in an interview with The PM Podcast that poor EVM performance at 20% is very unlikely to be made up without additional resources, additional funds, or a reduction in scope.
EVM also offers objectivity. It measures performance relative to a budget and baseline schedule. EVM’s performance indexes allow for comparisons between projects, even if their budgets or schedules are very different. It is possible to compare a 6-month project to a 6-year project using the same terms. It is a universal and objective measure that can be used to help project performance be visible to all stakeholders.
Why not EVM?
I have heard a few things that I disagree with about EVM. First, full-blown EVM can be too costly for small projects. Simple EVM was created for this reason and could be a good replacement for smaller projects.
EVM doesn’t take into account the critical path. EVM treats all work equally. This works well for cost performance, but not for schedule performance. It seems that, in addition to the SPI (scheduleperformance index), which I will detail later, there should also be an index that tracks progress along a critical path. This could be accomplished by simply comparing the critical path performance to the baseline. The SPI is more about the work done than the timeframe. These are two different ways to look at the performance of a project’s schedule.