Hi Micael,

I shared the same doubts you have when I first approached EVA, and I understand it could be confusing sometimes.

But I agree with Harry's explanation: the calculation of EV based on percentage of work completed equally applies to single tasks/activities (such as the foundation you mention in your example). What may help you to determine the percentage of completion, is the project schedule - which is typically provided to answer this kind of questions. Then, from there you will be able to derive the percentage of completion for each activity, while their PV are typically given. You sum up all the EVs associated to the completed activities (accounting for their percentage of completion), and you obtain the project EV.

As for the specific example you mention from Rita's book, this is exactly what they do: to compute the project EV, they start to compute the EV of each activity, based on their percentage of completion as of today. The first two activities have been completed, so EV_1 = PV_1 and EV_2 = PV_2. The third activity was expected to be completed by the end of Day3, but it actually was only 50% done at the time, so EV_3 = 50% * PV_3 = 500. You need to account for this effort on activity 3, which tells you that half of the work required for this activity has indeed been done; otherwise you would get misleading results when assessing how much your project is ahead/behind schedule.

Gabriella