PMP TEST TIPS
FREE FLOAT vs. TOTAL FLOAT
FREE FLOAT is a topic that students always have some trouble with in class, because it sounds like Total Float, but is different. Here’s the skinny for the PMP Test.
Free float is simply how much time there is between an activity and its successor activity.
Free Float is easier than the main kind of Float (Total Float), because with Free Float, you DON’T need to analyze for the Critical Path first.
TEST TIP:
And so a way to remember it is…
with Free Float you are Free of the Critical Path.
EXAMPLE #1
Suppose Ellen is planning to go for a drive at 12:00 PM and get an errand done.
She should be home about 1:00 PM.
At 3:00 PM she promised to lend her car to her friend Steve.
So she has 2 hours of Free Float between 1:00 and 3:00.
She needs to be home at 3:00 so Steve can come and pick up her car.
EXAMPLE #2 – Andy Crowe book, P. 262
The Project Network Diagram below is is From Andy Crowe’s book:
The PMP Exam: How To Pass On Your First Try
This diagram is asking for the Free Float for Activity “E”. Meaning how many days of Free Float are between “E” and its successor “C” as follows:
– “E” can’t start until Day 20, because it has to wait for “A” and “B” to complete.
This means the Early Start (ES) of “E” is Day 20, as follows:
“A” is 9 Days and “B” is 10 Days, so 10 + 9 = 19 Days, and the next day would be Day 20.
– E can’t complete until Day 15.
This means the Early Finish of “E” (EF) is Day 15, as follows:
“D” is 9 Days and “E” is 6 Days, so 9 + 6 = 15 Days, and E finishes on Day 15.
“E” ends on Day 15, and “C” starts on Day 20,
so after Day 15, there are 4 Days of Free Float:
- Day 16
- Day 17
- Day 18
- Day 19
On a calendar view, this would look as follows:
You can see 4 Days of Free Float in-between Day 15 and Day 20 (above)
ANOTHER TEST TIP:
You can also use the Formula For Free Float for the same example as follows:
For more help toward your PMP Exam…
1. My PMP Exam Prep class for NYU SPS
Next class starts Sunday, September 22
2. My Risk & Change Management class for NYU SPS
Next class starts Tuesday, November 19
3. My book: The Project Management Answer Book, 2nd Edition
4. My book: “Learn The PMP Keywords In Logical Pairs”
Only $3.99 on Amazon Kindle
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