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Last edited 14 Mar 2017
Schedule performance index (SPI)
The schedule performance index (SPI) is a measure of how close the project is to being completed compared to the schedule.
- A project has a budgeted cost of £120,000.
- According to the schedule, 15% of the project should have been completed after one month. That is £120,000 x 15 / 100 = £18,000.
- But after a month, only 12% of the project has actually been completed, at a cost of £10,000.
The schedule performance index (SPI) = 10,000 / 18,000
SPI = 0.55
If the ratio has a value higher than 1 this indicates the project is progressing well against the schedule. If the SPI is 1, then the project is progressing exactly as planned. If the SPI is less than 1 then the project is running behind schedule.
 Related articles on Designing Buildings Wiki
- Activity schedule.
- Cost performance index (CPI).
- Design programme.
- Earned value.
- Fast-track construction.
- Key performance indicators KPI.
- Lead time.
- Programme for building design and construction.
- Project crashing.
- Scheduling construction activities.
- Time management of construction projects.
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