The most dangerous sentence in construction is "we were the low bidder." The second most dangerous is "we were second and lost by $40,000 on a $4 million job." In the first case, you have probably miscounted something. In the second, you probably priced the job correctly and someone else made the mistake.
CFMA's 2024 Construction Financial Benchmarker Report, compiled from more than 2,700 contractor financial statements, lays the range out. It is narrower than most estimators think.
| Segment | Net Profit Margin (Median) | Top Quartile |
|---|---|---|
| Commercial GC (non-residential) | 2.3% | 4.1% |
| Electrical subcontractor | 3.8% | 6.5% |
| Mechanical / Plumbing sub | 3.1% | 5.9% |
| Civil / Heavy highway | 2.9% | 5.4% |
| Specialty (masonry, drywall) | 3.5% | 6.2% |
Source: CFMA 2024 Construction Financial Benchmarker, median figures by NAICS segment.
Read those numbers carefully. A commercial GC with a 2.3% net margin has a 43-cent margin on every $20 of work. If the takeoff is off by 3%, the job is a loser in absolute dollars. If it is off by 5%, the net for the year is gone across two jobs.
The survivor bias problem in public-bid data
When I worked on a federal IDIQ bench, we tracked every public bid that was opened in our region — 1,400 bid openings over seven years. The spread from low to second-low ran from 0.4% to 18%. The median spread was 4.6%. If you believe CFMA's margin data, a 4.6% spread is double the median industry net margin. The low bidder had already priced away the profit before the contract was signed.
What made that data useful was the follow-up: we tracked who completed each of those jobs. Of the projects where the winning bid was more than 7% below second, 31% ended in a change-order fight so large it put the job underwater, 14% ended with a replacement contractor called in under the surety's takeover provisions, and 9% ended with the winning contractor walking away from future work with that owner. The low-bidder pool is not the profitable-contractor pool.
This is survivor bias in reverse. We look at the contractors still in business and assume they won by being lowest. The graveyard of contractors is full of shops that won by being lowest. Nobody writes trade press stories about contractors that closed because they priced three jobs too tight in a row.
Where the low bidder actually made the mistake
MCAA's 2017 Factors Affecting Labor Productivity study — still the most cited productivity study in mechanical contracting — quantified the productivity losses from specific jobsite conditions. The headline finding: stacked trades and overcrowding reduce labor productivity by an average of 20%, and in severe cases by up to 38%. Weather exposure on rough-in adds another 10-15%. Overtime scheduled more than 8 weeks running drops productivity 20-25% on the overtime hours themselves.
The low bidder's estimate almost always assumes none of these losses. The base labor unit in the catalog. A 10% markup for general conditions. A 5% contingency. Done. The second-lowest bidder, the one who lost, usually built in the MCAA losses line-by-line because they have been burned before. They walked away with their margin intact and went to price the next one.
Applying contingency at the end of the bid as a percentage of total cost. Contingency is scope-specific risk money. Flat contingency does nothing when the risk is concentrated in labor productivity on a single stacked-trade phase. The MCAA productivity losses apply to specific activities, not to the bid as a whole.
A cost-recovery breakeven example
Say you bid a $3.2M commercial tenant improvement. Your cost estimate is $3.04M and you add a 5% fee to get to $3.19M. You win by $38,000 against the next bidder at $3.23M. Six weeks into the project, the GC stacks three trades in the same corridor, and your labor productivity drops 20% for eight weeks. Your labor budget for that period was $240,000. The 20% productivity loss adds $48,000 of labor cost, which now exceeds your entire fee.
The breakeven math:
Recovery revenue required = (added labor cost) / (expected gross margin on change orders)
To recover $48,000 through change orders at a typical 15% gross margin on CO work, you would need to write and have approved $48,000 / 0.15 = $320,000 of change-order value. On a $3.2M base contract, that is 10% in CO volume. Most commercial TI projects do not produce 10% in legitimate change-order volume. The recovery is mathematically out of reach, and the job finishes with zero fee — best case.
The contractor who bid $3.23M and lost? They went and bid a different job. They won one out of four. Their hit rate is lower, but every job they win has the 5% fee and a productivity cushion. At year-end, their net margin is in the CFMA top quartile. Yours is in the red.
Why "second-lowest" is usually the right number
There is an old preconstruction proverb: if four qualified contractors bid a job and you are lowest by more than 4%, find your mistake before you sign the contract. The proverb has a sound basis. Four independent estimators pricing the same scope with reasonable productivity assumptions should converge within the range of legitimate labor, subcontractor, and overhead differences, which is typically 3-5%. When the spread between low and the pack is bigger than that, the low number is almost always an error, not efficiency.
The most instructive thing an estimating shop can do is pull its last 24 months of bids and correlate the bid-spread variance with completed-job gross margin. The correlation runs in one direction, every time: the more you won by, the less you made. Jobs won by 1-3% deliver to plan. Jobs won by 6%+ lose money at the gross margin line, on average, in roughly 60% of cases.
"When we're lowest by more than 5% on a hard-bid public job, we treat it as a red flag and re-review the takeoff before we sign. Three times out of four we find the error. The one time we don't is the job we make money on."
Chief Estimator, Mid-Atlantic GC — confidential, 38-year tenure
The structural answer
The profitable response to the margin illusion is not to bid higher as a matter of policy. It is to bid more accurately, with explicit productivity loss factors, explicit stacked-trade contingencies applied at the activity level, and an explicit re-review protocol when the bid comes in materially below the pack. The top-quartile contractors in CFMA's data are not charging more than the median. They are pricing risk that the median is ignoring.
Most of the gap between the 2.3% median and the 4.1% top-quartile net margin is not a revenue story. It is an estimating-discipline story. The tools and the data already exist — MCAA's study, NECA's labor units, CFMA's benchmarks, RSMeans' city cost indexes. The shops that use them come in second a lot and make their year on the fraction of jobs they actually win.
PILRS gives your estimating team the accurate quantities to apply real productivity math to — not just base labor units. View pricing here and bid the number that reflects how the job will actually run.