Raj's Formulae

Raj went through the PMBOK and collected the formulae we need to know for the certification test.

Schedule Development

PERT Calculations



Uses values optimistic (O), pessimistic (P), and most likely (M) to determine project duration.

• Mean = (P + 4M + O)/6
• Variance = ((P – O) / 6)) 2
• Expected Value = (O + P + (4 x M)) / 6
  
• • Example: 60 days most likely, 72 days pessimistic, 48 days optimistic:
  • (48 + 72 + (4 x 60)) / 6

Standard Deviations

• Standard Deviation = (P – O) / 6
  
• Example: 60 days most likely, 72 days pessimistic, 48 days optimistic:
• (72 - 48) / 6
  

• Percent Probabilities
  
• • 68% ± one standard deviation
  • 95% ± two standard deviations
  • 99% ± three standard deviations

Cost Control

• PV - Planned Value
• EV - Earned Value
• AC - Actual Cost
• SV – Schedule Variance
• CV – Cost Variance
• SPI – Schedule Performance Index
• CPI – Cost Performance Index
• BAC – Budget at Completion
• BCWR – Budgeted Cost for Work remaining
• ETC = Estimate To Complete
• EAC = Estimate At Completion
• VAC = Variance At Completion
  

Earned Value Managment

• SV = EV-PV (old BCWP-BCWS)
• CV = EV-AC (old BCWP-ACWP)
• SPI = EV/PV (old BCWP/BCWS)
• CPI = EV/AC (old BCWP/ACWP )
• BCWR = BAC-EV
• EAC = AC + BCWR or EAC = AC + (BCWR/CPI)
• EAC = AC + BCWR or EAC = AC + (BCWR/CPI)
• ETC = EAC - AC
• VAC = BAC – EAC
  

Three approaches to calculating EAC

• EAC = AC + ETC
• EAC = AC + BAC - EV
• EAC = (AC + (BAC – EV) / CPI)

Circular Communication Network

• (number of participants (number of participants less one)) / 2
• (n x (n - 1)) / 2
  

• • Example: six participants
  • (6 x (6 - 1)) / 2