The break-even headcount

Parts 01 and 02 produced a cost per completed survey for one surveyor. The obvious next question is whether that number improves with scale. It does, in stretches, and then it gets suddenly and violently worse, and it keeps doing that forever.

The reason is that the two sides of the comparison have different shapes. Outsourced surveying is a straight line: every survey costs the same as the last one. In-house surveying is a staircase. You cannot hire four-tenths of a surveyor for the four-tenths of demand you just picked up.

The staircase, with numbers on it

Take a surveyor who completes 42 a month at the loaded cost from Part 01, and an outsourced price of 235 a survey, which is an assumption for the sake of the arithmetic and not a quote. Watch what happens across a single month of growth.

Two things to notice. The best in-house number never gets better than the number at perfect utilization, because a fully booked surveyor is the whole ceiling. And that best case only occurs at exact multiples of capacity, which real demand does not respect.

You do not pay for the surveys you did. You pay for the crew you kept.

Where the crossover actually sits

Everything above assumed one outsourced price and one in-house cost, and those are the two inputs most worth arguing about. Lower your loaded cost, or negotiate a worse outsourced rate, and the crossover moves. The model below finds it for your numbers rather than ours.

The part that is not about money

A staircase is not only a cost problem, it is a hiring problem, and hiring is slower than demand. The month you cross a capacity line is the month you need a surveyor who is already trained, already insured, already in the right metro. Nobody has that person standing by. So the real behaviour is not a clean step up, it is a quarter of overtime, slipped appointments and a design queue backing up while recruiting runs, followed by a step up that arrives after the peak has passed.

That lag is the actual cost of the switch, and it does not appear in any model on this page. It appears in turnaround time, which is what your sales team is selling against.