I think you mean TCSPI, there is no such thing as TSPI.
TCSPI stands for To Complete Schedule Performance Index.
The difference between TCSPI and SPI is the following:
- TCSPI and SPI are calculated differently, here are the formulas:
* TCSPI = (BAC - BCWP) / (BAC - BCWS)
* SPI = BCWP / BCWS
- From the formula above, if TCSPI goes above 1, then SPI goes below 1 (and the other way around). This means that if TCSPI is above 1, then the project is behind schedule.
TCSPI is meaningless and I've never seen it used.