*Dear PM Advisor,*

*I struggle with all the Earned Value Formulae. Any hints for making this portion of the PMP test easier to study for?*

*Can’t see the value in Albuquerque*

Dear Can’t,

Once you struggle with the more philosophical questions
on the PMP exam you’ll see the calculations like those Earned Value ones as a
breath of fresh air. But first let me give you some hints to make these easier
for you.

You are usually given some numbers and asked to
calculate the rest. I’m going to assume you know some elementary Algebra before
you take the test. Here are the three numbers you are usually given: Planned
Value (PV), Actual Cost (AC) and Earned Value (EV). If they are evil they will
give you one of the below calculations and you will need to use that basic Algebra
to determine the missing number from above. Either way, you’ll need to remember
the following formulae and below I’ll show you the easy way to do this.

There are four rules to remember:

- EV always come first in the calculation
- AC goes with anything that says Cost
- Negative Variances are always bad
- Indexes less than 1.0 are always bad

So let’s use these rules. You are asked
to calculate Cost Variance. You get Variances by subtracting one number from
another. Rule 1 says EV always goes first. Rule 2 says AC goes with any Cost
calculation.

Thus

**CV = EV –AC**Simple, right?
What does that leave you with for Schedule
Variance? EV goes first, Rule 2 is not
in effect so the only thing left to put in the equation is PV.

Thus

**SV = EV – PV**
The same two rules apply for the Index calculations.

Cost Performance Index requires EV to go first, only
this time the EV goes in on top of the line. We’re talking about cost so AC
goes on the bottom.

Thus

**CPI = EV/AC**
Schedule Performance Index, SPI, must use PV since that’s all that’s left.

Thus

**SPI = EV/PV**
Rules 3 and 4 help you convert formulae into
reality. If you have a negative SV, you are behind schedule. A negative CV
means you are OVER budget. Don’t get confused by the negative number. Negative
is bad, being over budget is bad.

Same with the indexes. Less than 1 is bad so a SPI
of 0.8 means you are behind schedule. Over 1.0 is good so a CPI of 1.2 means
you are UNDER budget.

Remembering these hints will help you with about 5
of the 200 questions you will be faced with. For the one or two questions that require TCPI or
ETC, you just have to memorize the formulae. More on these in a future post.

Good luck,

PM Advisor

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