- Project plans
- Project activities
- Legislation and standards
- Industry context
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.
Featured articles and news
Whole-life costs consider all costs associated with the life of a building, from inception to disposal. Find out more here.
Reports emerge of injuries caused by Apple employees colliding with the campus' glazed walls.
The winners of NIC's ideas competition on transforming the Cambridge to Oxford arc discuss their concept.
Create new habitats and improve air quality and wellbeing.
New report provides 12 key actions which could close the structural talent gap in the construction industry.
These can be used to find out whether a proposed development is likely to be approved. Read more here.
Studying a built environment degree? Check out our helpful student resources section.
New BRE research paper explores how blockchain technology can benefit the built environment industry.
Timber is a natural carbon sink, but it must not end up in landfill at the end of its useful life.
BSRIA has collaborated with the Department of Health on research into air permeability in isolation rooms.