Not all great ideas in project planning are compatible. One of the more common problems I see in client's efforts to apply EVM is the level of detail planning. It's not that the planning has too little detail, it has too much detail!
 
There is a notion that tasks should be scheduled down to 80 hour efforts. In general the idea of decomposing work to a detailed level is a great idea. It shows what is known about the work, what is not known, and a roadmap of work for the project staff to follow.
 
I support detail planning, but it has to fit the work and not all work lends itself to 80 hour increments. So, first, plan to the detail that the knowledge and nature of the work allow. Normally MS Project and similar tools ask the user to provide a budget or resources to complete the work. Not a bad idea. Done right this can help make sure the overall budget addresses all the work to be completed.
 
But here is a problem. When the project gets underway we feel the need to record costs to the levels budgeted. This leads to a plethora of project charge numbers for all those accounts of 80 hours or more or less. At the end of the day or week our staff knows they worked on the project every day. But which of these many tasks and how much time was worked on each? So they look over all the "open" charge numbers and select some to record their time spent on the project. The total is correct but the detail is really questionable.
 
And here is the real problem. If we let MS Project or other tools compute percent complete task-by-task from the recorded hours (costs) there is little accuracy in our EV.
 
What is the solution? One...Record costs at a higher (WBS) level in the project so that there are fewer charge numbers. People tend to work within a few WBS at a time so sorting out the charges at the end of the day or week is easier and thus more accurate. Two..Estimate EV by reviewing work products. EV cannot be computed from funds spent. Manually enter "Physical Percent Complete".
 
What to do with all the detail planning? Make them EVM work packages! Work packages need budgets per ANSI 748, but cost collection is not required. (We just need to know the big ones from the small ones.) You get the benefit of better estimates of EV and more accurate AC from properly recorded costs.
 
 
Next month. More detail planning or lower cost estimates, pick one - how to decide.