Order of magnitude
I have a little bit of difficulty with this formula here,
If order of magnitude spread is -50% to +50%
And the actual cost of project is $100,000
Then 50% of it is $50,000
So the range will be $50,000 to $150,000,
However on some prep material that I have found, a project with target price of $100,000, has a range of $75,000 - $175,000 with this level of estimation. Is this because anything higher than %50 i.e. 75% is also considered rough order of magnitude?
Please help me understand this.
By the way I think I found a typo in my prep book , on page 169 of "The PMP Exam, how to pass on your first try, Andy Crowe", it says the order of magnitude estimate ranges from -50% to +100%, do you think that's a typo or am I missing something?


Order of Magnitude
Hi
Yes you are right. Order of magnitude, in every book it differs. As per PMBOK v 4, it is mentioned 50% (+ or -) and we should go by PMBOK.
Also, it is mentioned that definite magniture is 10% (+ or -) and budgted not mentioned. In some other book it is mentioned that -10% to 25%.
If anyone is having different openion, please let me know. Thanks