Portfolio Composite Index
Three-step formula — weighted CPI & SPI with a 70/30 blend
What the letters mean
CPI — Cost Performance Index. Are you on budget?
SPI — Schedule Performance Index. Are you on time?
w — Weight of each project (by budget, priority, etc.). All weights add up to 1.
1
Portfolio CPI
Blend each project’s cost performance using its weight.
Portfolio CPI = w₁×CPI₁ + w₂×CPI₂ + … + wₙ×CPIₙ
Multiply each project’s CPI by its weight, then add them up.
2
Portfolio SPI
Same thing, but for schedule performance.
Portfolio SPI = w₁×SPI₁ + w₂×SPI₂ + … + wₙ×SPIₙ
Multiply each project’s SPI by its weight, then add them up.
3
Combined Performance Index
Blend the two numbers — cost counts for 70%, schedule for 30%.
PI = 0.7 × Portfolio CPI + 0.3 × Portfolio SPI
Take 70% of the cost score, add 30% of the schedule score.
Worked Example
Three projects, equal weight
Each project counts for ⅓ of the portfolio.
Reading the Score
What the number tells you
= 1.0
Exactly on plan
> 1.0
Trending favorably — under budget / ahead of schedule
< 1.0
Trending unfavorably — over budget / behind schedule
Sources:
- Moi Hoon Yap, Ryo Hachiuma, A. Alavi, Raphael Brungel, M. Goyal, Hongtao Zhu, B. Cassidy, Johannes Ruckert, M. Olshansky, Xiao Huang, H. Saito, S. Hassanpour, C. Friedrich, D. Ascher, Anping Song, Hiroki Kajita, David Gillespie, N. Reeves, Joseph M. Pappachan, C. O’Shea, E. Frank. 2020.
- Iacopo Vagliano, N. Chesnaye, J. Leopold, K. Jager, A. Abu-Hanna, M. Schut. 2022.
- Abdelhafid Zeroual, F. Harrou, Abdelkader Dairi, Ying Sun. 2020.
- Kyung-Ok Cho, Hyun-Jong Jang. 2020.
- Nicolas S. Bodmer, Dylan G. Christensen, Lucas M. Bachmann, Livia Faes, F. Sanak, K. Iselin, C. Kaufmann, Michael A. Thiel, P. Baenninger. 2024.
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