TOPIC: Resources, Costs... What is the first?

Good day, colleagues!

When I read Annex A1 I see, that Cost Estimates are the input to Estimate Activity Resources process. It looks strange. As I understand we Define Activities first. Then we should determine the Resources, required to accomplish these Activities together with the amount of these resources (I mean quantity of goodies and effort for people's work). And only then we can calculate the cost. So, how Cost Estimates (an output of the Estimate Costs process) could be an Input to Estimate Activity Resources?

Hi there,

if I got you correctly you mean A1.5.13 Estimate Costs in Annex A1 Ion page 436 right?

If so let's jump in the whole chapter 7. Project Cost Management to the process 7.2 Estimate Costs.
Here you can read that the Output of this process goes to "Activity cost estimates"
and in the process "Estimate Costs" you put costs behind your work, risks.. with support of several T&T mentioned on this page.
Once you have the costs you can calculate the budget.

You wrote "input to Estimate Activity Resources process" and indeed I found that not in the ITTO on page 200 but on
the figure on page 201. I guess this is to describe the continuous loop of refining the costs. So if you have the costs and maybe want to go back and check if you can improve with different resources...
The third paragraph on this page is about that : Cost estimates should be rviewed and refined during...

Please let me know your thoughts.

Cheers
Sven

Aleksey,

Sven is absolutely correct. This shows the integrated and circular nature of the processes described in the PMBOK Guide. The processes and their ITTOs interact in many ways that can simply not be shown in graphics and lists.

So the very first time that you will go through the process of Estimate Activity Resources you correctly realized that you will not yet have the full "activity cost estimates" as your input. But this is the moment when your brain will kick in. And your brain will tell you... "I know that both Susan and Joe can do this job well. Susan has an hourly rate of $110 and Joe is at $105. So which one of the two should I be using considering this...?"

So as you can see from this example, even though the processes are described separately in the PMBOK Guide, there are moments when you jump from one to the other and back again in an instant.

So to answer your question in the topic: "Resources, Costs... What is the first?". The answer for your particular case is... neither. They are happening at the same time to achieve the desired result.

"the integrated and circular nature of the processes..." sounds in a very wide manner ))) But I agree, that activity cost estimates could either be or not be an input to estimate resources depending on the moment of time. Thank you for the explanation. That is important. You don't have to use ALL the inputs described at every single pass.