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.

As a ratio it is calculated by dividing the budgeted cost of work performed, or earned value, by the planned value.

For example:

• A project has a budgeted cost of £120,000.
• According to the schedule, 15% of the project should have been completed after one month (planned value). That is £120,000 x 15 / 100 = £18,000.
• But after a month, only 12% of the project has actually been completed (earned value). That is £120,000 x 12 / 100 = £14,400.

SPI = EV / PV = 14,400 / 18,000 = 0.8

This means that for every estimated hour of work, the project team is only completing 0.8 hours (just over 45 minutes).

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.

[edit] Related articles on Designing Buildings Wiki

• Activity schedule.
• Cost performance index (CPI).
• Benchmarking.
• 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.

[edit] External references

• Schedule Performance Index

Comments

Its just 12/15 no need to multiply the percentage by the budget.

Indeed.