This document provides formulas for calculating key project management metrics such as net present value, PERT estimates, expected monetary value, communication channels, float, earned value, variance, performance indexes, estimates, and burn rate. Formulas allow calculating the time, cost, and schedule performance of a project for monitoring and control purposes.
2. Net Present Value (NPV) used for project selection
Always select the project with the highest NPV.
Year 0 Initial Investment
Year 1 + Cash Flow 1 / (1 + Discount Rate) 1
Year 2 + Cash Flow 2 / (1 + Discount Rate) 2
Year 3 + Cash Flow 3 / (1 + Discount Rate) 3
(and so on for as many years as cash flow is given)
3. Program Evaluation and Review Technique (PERT)
PERT / Weighted Duration / 3-Point estimate
Triangular
distribution
Beta distribution Standard Deviation
[O+ML+P]/3 [O+ (4*ML) +P]/6 SD = (P-O)/6
Only use this if the
question specifies
that all inputs
should be weighted
equally
Default to this unless
question specifies that
all inputs are weighted
equally
Reserve time
4. Risk Rating (qualitative risk analysis)
Used during qualitative risk analysis
Risk Rating = Probability x Impact
Answer is expressed as a % or decimal
5. Expected Monetary Value (EMV)
Used during quantitative risk analysis
Expected Monetary Value = Probability x Impact
Answer is expressed as a $ amount
6. Communication Channels
Number of communication channels = n(n-1)/2
Remember, if you are working with other team
members, add 1 to count yourself
If the question asks you how many more you will
need to calculate twice. Once for the original state
and once for the new state. Subtract the two values.
7. Make or Buy Analysis
This is an equation rather than a formula.
Use the equation to find the break-even point.
Cost to Make = Cost to Buy (Lease)
To find the breakeven point, place the cost to make and the cost to buy on either side of the
equation. Solve for X, which is the variable (# of days).
e.g. Initial cost to make + (Daily cost to make* X) = Cost to lease + (Daily cost to lease * X)
Make Lease Total Make Total Lease
Initial Cost $12,000 $2,000 $12,000 $2,000
Day 1 $25 $350 $12,025 $2,350
Day 2 $25 $350 $12,050 $2,700
Day 3 $25 $350 $12,075 $3,050
Day 31 $25 $350 $12,775 $12,850
At day 31 the Lease
costs begin to
outstrip the Make
costs this is the
breakeven point
11. Actual Cost (AC)
The amount of money spent on approved project work to-date.
This number is usually given to you. It may also be presented as
Budget at Completion (BAC) Money Left = AC
16. Estimate at Completion (EAC)
There are four different formulas based on different scenarios
Scenario #1: Assumes the same rate of spending will continue
EAC = BAC/CPI
Scenario #2: Assumes you have deviated from the budget due to a one-time incident, but spending would
have otherwise been on track with the plan and will continue at the planned rate going forward
EAC = AC + (BAC EV), or this formula can be formatted as
EAC = BAC CV
Scenario #3: Cost performance has been poor and project deadline is firm
EAC = AC + {(BAC-EV)/(CPI x SPI)}
Scenario #4: Assumes the original budget was flawed. The formula considers actual cost, and reassesses
the cost of all remaining work (Estimate to Complete, or ETC).
EAC = AC + ETC
18. To Complete Performance Index (TCPI)
work left / money left
TCPI = (BAC-EV)/ (BAC-AC)
or
TCPI = (BAC-EV)/ (EAC-AC)
Replace BAC with EAC if budget has been rebaselined
19. Variance at Completion (VAC)
VAC = Budget at Completion (BAC) Estimate at Completion (EAC)
20. Burn Rate
Burn Rate = 1/Cost Performance Index (CPI)
Burn rate < 1 means budget is being utilized slower than planned
Burn rate > 1 means budget is being utilized faster than planned