9 / 2019-02-22 00:18:43

Homogenizing Project Schedule Performance Index (SPI)

SPI Index,,Homogenizing Schedule Performance Index,,Planned Financial,,Actual(Performed) Financial,

Schedule Performance Index (SPI) is one of the Earned Value Method indicators for assessing a project performance schedule. The SPI index can be determined through dividing actual progress by planned progress:
SPI=Actual/plan=(%A)/(%P)=(Earned value)/(planned value)=(%AxBCWS)/(%PxBCWS)
The SPI index indicates our performance compared with the project scheduling:
1. If the SPI is greater than one, this means more work has been completed than the planned work. In other words, you are ahead of schedule. In this case, our project scheduling is likely to have technical problem.
2. If the SPI is equal to one, this means work is being completed at about the same rate as planned, you are on time.
3. If the SPI is less than one, this means less work has been completed than the planned work. In other words, you are behind schedule.
The problem with this index while actual implementation of project for measuring a project scheduling performance is that the denominator and numerator are not homogeneous. That is, the numerator (actual) is usually determined by (Done Volume)/(Planned Volume) and denominator by (Passed Duration)/( Total Duration). In other words, the numerator is made of volume and the denominator of time. Therefore, the SPI index does not provide project managers with precise guidelines for indicating a project's actual performance in terms of time and project implementation. Therefore, it is necessary to obtain a practical method for homogenizing the numerator and denominator of this indicator that not only provides a precise criteria for a project schedule performance but also proper guidelines to make on-time and correct decisions by project managers and administrators. This paper aims to present a method for this purpose by giving an example of unit price contract in one of the real civil projects.