TOPIC: Pert related question

When to use Pert = (o + 4m + p) /6 formula
and when to use = (o + m + p)/3?

Thanks

Dear Mohammed:

Good day and thanks for asking a great question.

Usually, the question would mention which formula to use. However, if a question doesn't mention that, go with the PERT formula.

Warm regards,

Khurram Hussain, PMP, CSSBB

Thanks Khurram for your response. I am a new user and this is my first post.

Actually I was planning to post a question on this (three point estimate vs PERT) but then saw and read Mohammed's post. So if the question does not mention whether to use PERT or three point estimate and answers have both choices (M+O+P)/3 and (4M+O+P)/6, we should go with PERT, right?

Actually I read in some books about both but I think PMBoK only mentions PERT.

Sorry for asking I believe the same question again, may be some other PMP's may chime in with their experience/response.

Thanks, Bharat.

Dear Bharat:

Good day and thanks for your message!

Actually PMBOK does mention both of the concepts. So if a question is asking about an estimate and not mentioning which technique to follow (directly or indirectly), I would recommend going for the PERT estimate as it puts more weight on the most likely estimate. In the real PMP exam, you will not encounter a situation where a question asks for an estimate, doesn’t directly or indirectly points out to the required technique, and have both simple average and PERT estimates as the answers to two of the given choices. Such ambiguous questions are usually eliminated out of the exams. However, you will see such question in exam simulators and sample question banks on the internet, as the idea there is to have more difficult questions for the training and learning purposes.

I hope this answers your concern. Let me know if it doesn’t.

Regards,

Khurram Hussain, PMP, CSSBB

Great, very well said and explained.
Thank you.
Regards, R.