I wondering how engineers and architects come up with construction estimates for projects. I've done a lot of design work but when someone asks me how much it should cost to build I have very little to go on, not being a contractor. How are design professionals approaching this?
How do engineers and architects develop estimates of a project cost?
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petersonra
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- Northern illinois
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- engineer
Construction estimates are often based off similar projects or other projects that can scale up or down to the project being estimated.
There are also some books you can buy (or probably apps these days) that will help you make such guesses. They are remarkably accurate given how vague many projects are at the estimating stage.
RumRunner
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- SCV Ca, USA
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- Retired EE
Have you ever tried the PERT Technique? (Project Evaluation and Review Technique). At this level of conceptual stage where there is nothing to go by, estimates are based on the equation:
Estimate = (O+4M+P)/6.
In this weighted result where:
P= most pessimistic (things go wrong)
O=most optimistic (things go right)
M=normal problems (things with normal problems)
Since there are no plans, specs and drawings etc at this stage, high level of uncertainty exist coupled with numerous variances. Demands good judgment but at least some headstart. Isn't that what engineers are made of? :roll:
Look under PERT sites. Google is a good friend.
My wife is a retired Architect-- also a real good friend.:lol:
RumRunner
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- SCV Ca, USA
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- Retired EE
My pleasure.
Coppersmith
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- Tampa, FL, USA
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- Electrical Contractor
Ran some numbers through the formula. Looks like garbage in, garbage out to me.
RumRunner
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- SCV Ca, USA
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- Retired EE
So, it's not OK to present reasonable argument and be labeled RUDE while someone calling one's comment with good intentions GARBAGE.
I don't see the acceptable behavior on the latter.
The end justifies the means.
But that's OK, all my posts are archived to be reexamined later.
I don't see the acceptable behavior on the latter.
The end justifies the means.
But that's OK, all my posts are archived to be reexamined later.
You are welcome to post a rebuttal to the method being challenged (called garbage), what you need to curb is direct personal attacks on others and your mindset that an EE is on some pedestal to be admired.
Roger
RumRunner
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- SCV Ca, USA
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- Retired EE
Where is the method that is used to challenge the method ?
Saying only that it's garbage without any rebuttal is not a challenge , rather to discredit what was being said.
It is not glorifying the status of EEs, I come head to head with anyone EEs or not when there's something that needs clarification--and I respect everyone's opinion and not call their words GARBAGE.
Is calling my words or others garbage not a personal attack?
Why didn't you simply ask Coppersmith that question?
And I agree, but you can ask for a persons reasoning without calling them ignorant.
So why do you specifically use the title of EE as some elevated status over an Electrician? (Yes you have done it here and in other threads)
Not in my opinion, he is saying that the way he sees it is garbage, reply to him substantiating what you have posted and hopefully have a civil disscussion.
Roger
RumRunner
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- SCV Ca, USA
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- Retired EE
I have voiced my answer for someone who needs an answer. No one was saying a pip to satisfy OPs needs. When I came along and tries to help, based on acadamic principles, I was put on the stakes to burn.
Why don't you bring up your own in your own words and research that nullifies the accepted practices by scholars and prove your point that it is indeed garbage.
Otherwise this exchange would be fruitless.
BTW: my answer to all your argument was on that post that someone decided to have vaporized.
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Calm down, you getting yourself all worked up and are confussing me with the member that called it garbage, I don't care about the topic of this thread, but I will keep an eye on it if that's any consolation.
Roger
RumRunner
Senior Member
- Location
- SCV Ca, USA
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- Retired EE
When someone's opinion-- whether it is right or wrong were given any significance by another, that person giving credit becomes complicit.
Does that sound like I'm flying off the handle?
Let me give you some advice, you need to thicken your skin a little, you will be challenged at times if you're posting on these forums.
That doesn't mean others can call you ignorant, stupid, an idiot, etc..... and on the flip side you can not call others names or try to belittle them with something as lame as a salary or pay scale, many electricians make more than EE's believe it or not.
Your ideas may or may not be challenged and you should defend those ideas but you should also be open to the fact that an apprentice electrician might just educate you on something.
With that said, my apologies to the OP but this thread has gone severely off track so I'm closing it.
Roger
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- Location
- Wisconsin
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- PE (Retired) - Power Systems
When I read Coppersmith's post, my reaction was that he was using a common 'computer programming phrase'. If you put garbage data into your formula, then results you get will also be garbage.
IMO. the OP is really asking how to determine your parameters M, O, and P.
Coppersmith
Senior Member
- Location
- Tampa, FL, USA
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- Electrical Contractor
This is exactly what I was saying. It was not an attack on anybody's character.
Since M, O, and P are essentially guesses, the formula averages three guesses and comes up with an answer that is meaningless.
For your enlightenment: https://en.wikipedia.org/wiki/Garbage_in,_garbage_out
RumRunner
Senior Member
- Location
- SCV Ca, USA
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- Retired EE
As I had mentioned earlier this is a graduate engineering studies under PERT/CPM (critical path method) Some colleges offer these courses.
The amount of lessons that cover this course would not be covered by a few posts here in this thread.
There are nine divisions to be covered and each division has to be completed before you can be eligible to move on to the next one.
The US Navy initiated this and is now being used by private companies.
The numbers that you are expecting to represent the part of the equation (M, O, P) is way down to the third or fourth division.
This is the lesser intelligent division after all the brain work that were done by the first three.
Think of this as the OSI model in software architecture/engineering, which, the hardware part is the least intelligent layer .. .this is where the numbers appear.
The conceptual part being the topmost layer in the OSI. (the most intelligent)
Does that make for garbage to you. . . or am I just talking nonsense.
gadfly56
Senior Member
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- New Jersey
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- Professional Engineer, Fire & Life Safety
You can haunt the online trade mags, they publish articles from time to time about square foot estimates. The problem is that such things are good only for rough-order-of-magnitude (ROM) project costs, and particular project conditions can help or hinder such procedures. RS Means is a popular estimating book/software if you're looking for more detailed estimates. Helpfully, they know that what it costs to put in a 1900 box in Topeka KS is very different than in New York NY. You can also look on line for cost estimating handbooks. Various branches of the federal government publish them as well and you might skim them for some ideas.
As a designer, you really shouldn't be harassed for cost information unless it's part of your job, in which case someone should pony up the funds to get you properly trained.
Coppersmith
Senior Member
- Location
- Tampa, FL, USA
- Occupation
- Electrical Contractor
I think you made my case for me
So apparently the formula above cannot be used without study in the nine divisions. No wonder I didn't understand it. I'm nowhere near edumakated enough. Thanks for the info.
OK Roger. I've had my say. You can close'er down now.
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