There is a cost in every bid that shows up on no line item. It was measured once, at national scale, more than twenty years ago. As far as I can tell it has never been measured on an individual job.
I wrote separately about why no two architecture firms draw a plan set the same way, and about the one place I could confirm anyone actually requires them to, a repeat federal buyer with enough leverage to make it stick. Almost nobody else hiring an architect is in that position. What I did not get into there is what that variance costs the people who have to read someone else's set and put a number on it.
Before anyone can start counting anything off a new set, they usually have to relearn that particular firm's habits first, how it numbers rooms, what its cross references mean, which code means which material. I have not seen anyone bill that separately. It gets folded into estimating taking a while.
The part that actually costs money is not the relearning. It is what happens when something in it gets missed. You do not get an error, at least not one anyone catches right away. You get a confident number that looks exactly like a right one.
From there it goes one of three ways and none of them are good. Guess low and you win the job and eat the difference once it shows up in the field, on a margin that was never priced for it. Guess high and you lose the job to whoever guessed lower, whether or not their guess was actually right. Or you stop and ask.
That third one is slower than it sounds. The clearest measurement I could find of the industry's formal channel for an ambiguous drawing, a 2013 analysis by the Navigant Construction Forum, put the median reply at 9.7 days. Two caveats on that figure, both real. It measures RFIs raised during construction, not questions asked during bidding, which run through a different mechanism on a different clock. And its data is drawn mostly from projects in Australia and New Zealand. So it is evidence that the formal channel can run slow, not a measurement of anyone's bid window. What I have not found a study for, and am reasoning from what I have watched instead, is how the same ambiguity plays out earlier, at the bid, where the deadline is usually tighter and moves for nobody.
Before I go further I should say what I found when I checked whether anyone had studied this, because it changed what I think the actual problem is.
Somebody did put a number on it. NIST commissioned a study that priced inadequate interoperability across the US capital facilities industry, and named a lack of standardization among its causes. That was measured in 2002.
I am not going to quote a twenty-plus year old figure at you as though it describes this year, and if anyone does that in a sales deck you should discount it. The reason it is worth raising is the opposite of a statistic. The aggregate has been on the record, from a federal standards body, since before a lot of people currently estimating were in the trade. And it did not change what happens on a single job.
Because what still does not exist, as far as I can tell, is that cost showing up anywhere on the job where it occurs. A change order gets coded to design error. An RFI gets logged under whatever it asked about. The hours somebody spent learning to read one firm's conventions before they could price anything get coded to estimating. Nobody has to be hiding anything for this to happen. There is simply no field for it.
That gap is the thing I keep coming back to. A cost with a national estimate and no local line item is one everybody can agree is real and nobody has to own. Twenty years of knowing the number in aggregate has not put it on a single job's books, and it is very hard to build the case for fixing something that never appears where it actually happens.
That is part of why I build the document-reading side of Setmark the way I do, to read a set's own conventions instead of assuming one firm's habits apply to the next. It still expects a person to check its reads, that is the point of it, not a shortcut around one.