How would a project manager use the CPI? The cost performance index (EV/AC) is a popular index. An index of .60 indicates that 60 cents of work has not been completed for each actual dollar spent. This would suggest to the project manager that the project will be under budget. The cost performance index (EV/AC) is a popular index. An index of .60 indicates that 60 cents of work has been completed for each actual dollar spent. This would suggest to the project manager that the project will be over budget or big savings in remaining work will be needed to bring the project in on budget. The cost performance index (EV/AC) is a popular index. An index of .60 indicates that 60% of work has been completed for each wbs. This would suggest to the project manager that the project will take longer or items will need to happen sonner in remaining work to bring the project in on budget