Brain Dump Formulas

Question 1

[n*(n – 1)] / 2

Answer 1

(# of) Communication Channels Equation

n = number of stakeholders on the team, incl the project manager.

Question 2

(Optimistic + Most Likely + Pessimistic) / 3

Answer 2

Three-Point Estimation Formula (aka Triangular Distribution)

Use for Scheduling and Cost Estimates

Optimistic = What is the best-case that will occur?
– Most Likely = Realistically speaking, how long would it take/how much would it cost?
– Pessimistic = What is the worst-case estimate that would occur?

Question 3

(Optimistic + 4*Most Likely + Pessimistic ) / 6

Answer 3

PERT Estimation Formula (“Beta Distribution”)

Use for Scheduling and Cost Estimates
Optimistic = What is the best-case that will occur?
– Most Likely = Realistically speaking, how long would it take/how much would it cost?
– Pessimistic = What is the worst-case estimate that would occur?

Question 4

LS – ES or LF – EF

Answer 4

Critical Path Analysis Formulas

If Float = 0, then the activity is on the critical path
If Float < 0, then the activity is Behind Schedule!

– LS = Late Start = Latest time that a task can start, without delaying its Late Finish
– ES = Early Start = Earliest time that a task can start
– LF = Late Finish = Latest time that a task can be completed, without affecting a Successor Activity
– EF = Early Finish = Earliest time that a task can finish

just think that a negative float is bad (bad for being behind schedule).

Question 5

EV – PV

Answer 5

Earned Value Analysis (EVA):
Schedule Variance, SV

– EV = Earned Value = The ACTUAL value for the work which has been “earned” or completed thus far.

– PV = Planned Value = The “planned” approved budget for completing the scheduled work

SV < 0 means… Behind Schedule (BAD)
SV = 0 means… On Schedule (NEUTRAL)
SV > 0 means… Ahead of Schedule (GOOD)

Question 6

EV – AC

Answer 6

Earned Value Analysis (EVA):
Cost Variance, CV

– EV = Earned Value = The ACTUAL value for the work which has been “earned” or completed thus far.
– AC = Actual Cost = How much was actually spent to perform the work?

CV < 0 means… Over Budget (BAD)
CV = 0 means… On Budget (NEUTRAL)
CV > 0 means… Within Budget (GOOD)

Question 7

BAC – EAC

Answer 7

Earned Value Analysis (EVA):
Variance At Completion, VAC

Budget at Completion (BAC) is a measure that is often used in earned value management to track the actual cost of a project against its forecasted budget.

Equivalent annual cost (EAC)

Question 8

EV / PV

Answer 8

Index Equations: SPI
SCHEDULE PERFORMANCE INDEX = EARNED VALUE / PLANNED VALUE

SPI < 1 means… Behind Schedule (BAD)
SPI = 1 means… On Schedule (NEUTRAL)
SPI > 1 means… Ahead of Schedule (GOOD)

Question 9

EV / AC

Answer 9

COST PERFORMANCE INDEX= (EARNED VALUE / ACTUAL COST)

CPI < 1 means… Over Budget (BAD)
CPI = 1 means… On Budget (NEUTRAL)
CPI > 1 means… Within Budget (GOOD)

Question 10

(BAC – EV) / (EAC? – AC)

Answer 10

To-Complete-Performance Index, TCPI
(BUDGET AT COMPLETION - EARNED VALUE) / EASTIMATE AT COMPLETION - ACTUAL COST)

When to use? Measuring the cost efficiency in order to complete the project per the plan

**Note: In the above two equations for TCPI, BAC is replaced with EAC in the denominator of the equation.