In measuring progress variances in a project, what is more important SPI or CPI?and why?

SPI and CPI both are important.

The Schedule Performance Index indicates how efficiently you are actually progressing compared to the planned project schedule.

As per the PMBOK Guide, “The Schedule Performance Index (SPI) is a measure of schedule efficiency, expressed as the ratio of earned value to planned value.”

The Schedule Performance Index gives you information about the schedule performance of the project. It is the efficiency of the time utilized on the project.

The Cost Performance Index helps you analyze the efficiency of the cost utilized by the project. It measures the value of the work completed compared to the actual cost spent on the project.

As per the PMBOK Guide, “The Cost Performance Index (CPI) is a measure of the cost efficiency of budgeted resources, expressed as a ratio of earned value to actual cost.”

The Cost Performance Index specifies how much you are earning for each dollar spent on the project. The Cost Performance Index is an indication of how well the project is remaining on budget.

Both of SPI&CPI Are imortant Where SPI=E.V/P.V&CPI=E.V/A.C so we can measure the Poject Progress Aganist Cost baseline and Schedule baseline and then indicate by (SPI)if the Project behined Schedule or not ‘also by(CPI) we can idicate if the Project is Over Budget or Under Budget. where: SPI:Schedule Performance Index&CPI:Cost Performance Index & E.V:Earned Value &P.V:Planned Value &A.C:Actual Cost

Both SPI & CPI are important for project success. SPI will give the variance whether we are behind schedule or ahead of schedule and CPI will show whether we spent more or less as per budget.