Rules of Thumb for estimating design effort
Rules of Thumb for estimating design effort
(OP)
Not sure this is quite the right forum, but I'll give it a shot...
I'm looking for some quick "gut check" type rules-of-thumb for estimating engineering design effort on projects. I recognize that a proposed fee needs to be based on the estimated effort to complete a given scope of work, but what about coming up with a quick estimate of effort?
Do you use percentage of construction cost?
Do you base it on number of plan sheets expected?
How do you separate preliminary design effort from the final design effort?
Thanks for your thoughts!
I'm looking for some quick "gut check" type rules-of-thumb for estimating engineering design effort on projects. I recognize that a proposed fee needs to be based on the estimated effort to complete a given scope of work, but what about coming up with a quick estimate of effort?
Do you use percentage of construction cost?
Do you base it on number of plan sheets expected?
How do you separate preliminary design effort from the final design effort?
Thanks for your thoughts!





RE: Rules of Thumb for estimating design effort
The higher the costs, the less the percentage....say 6-8% of construction costs.
I've seen estimates broken down into sheets, if they are well defined.
Regards,
![[pipe] pipe](https://www.tipmaster.com/images/pipe.gif)
Qshake
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
RE: Rules of Thumb for estimating design effort
But, the basic idea is that if you know what scope you did in the past and the amount of workd involved, you can ratio a new proposal's scope, and roughly determine an estimated cost.
In aerospace, it's often found that the initial bottom's up bid was the most correct, and that the "scrubbing" that ensues generally degrades the verisimilitude of that original bid.
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: Rules of Thumb for estimating design effort
Qshake's advice is probably as good as you are going to get. Allot of the answer depends on the complexity of the project. The only danger in using a % mark up is that on a simple project with say a huge pipe order, it could be skewed somewhat. But then again, if you are looking at some order of magnitude shot at it, a % will get you there - in oil & gas projects, we typcially see engineering costs at 5%-10% of TIC. If you see much above 15%, I would start looking for a reason.
Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website: www.oil-gas-consulting.com
RE: Rules of Thumb for estimating design effort
Even a range of 5-10% is a huge difference and would probably see you coming in as the cheapest or the most expensive.
Just out of interest, in structural work would you actually know the price of the project to quote design against? This is rarely the case in automotive.
RE: Rules of Thumb for estimating design effort
KENAT, probably the least qualified checker you'll ever meet...
RE: Rules of Thumb for estimating design effort
RE: Rules of Thumb for estimating design effort
http://www.eng-tips.com/threadminder.cfm?pid=784
They should have some good ideas....
Tobalcane
"If you avoid failure, you also avoid success."
RE: Rules of Thumb for estimating design effort
Of course not all projects are created equal and rules of thumb are only about as accurate as using your thumb to measure the pyramids - so be careful. As always, run it by management
RE: Rules of Thumb for estimating design effort