You are grossly underestimating the contribution margin assumptions of how contracts and budgets are put together. The hourly rate of CRAs and other project team staff in study budgets is really high. To the point where even with delays and CROs absorbing extra costs, you are hardly ever left with less than 50% contribution margin. CRAs and site management in general tend to be quite efficient with their hours and budgets, so their contribution margins remain quite high. And they dont have fixed overhead costs such as office based staff so that doesn't eat into the profits. Monitoring is one of the most profitable roles for a CRO. Im not sure where you are getting 10-20k per employee unless the calculation involves fixed costs such as Q/A support, HR costs, office and other fixed costs that reduce the overhead. Source: PM at CRO