(1) Explain your problem, don't simply post "This isn't working". What were you doing when you faced the problem? What have you tried to resolve - did you look for a solution using "Search" ? Has it happened just once or several times?
(2) It's also good to get feedback when a solution is found, return to the original post to explain how it was resolved so that more people can also use the results.
It seems it's only calculates the completed activities and does not include not started, in-progress, Milestone, WBS Summary and LOE are also not included. See below:
BEI - Baseline Execution Index: Mark to analyze the number of completed activities in the project against the number of baseline activities calculated to finish before the open project's data date. Not started activities, in progress activities, Milestones, WBS Summary activities, and Level of Effort activities in the open project are not included in this analysis. In the project baseline, milestones, WBS Summary activities, Level of Effort activities, and activities with a finish date later than the open project's data date are not included in this analysis. Specify the target for the acceptable ratio of completed activities in the open project compared with baseline activities scheduled to finish before the open project's current data date, as expressed as a percentage.