The Impact of Labor Shortages on Construction Estimating

I'm a building estimating professional specializing in resource planning by managing labor appropriately and I want to share what I know about labor shortages in this forum. I've been a part of such projects recently and I know how the lack of personnel can do havoc with estimations, especially when specialized workers are expected but are not present as per the schedule. It’s not only the schedule that gets extended but the cost that is projected. Have you experienced this in your work? To make it even more complicated, services like waterproofing estimating services which want to get proper labor estimates are necessary in order not to end up in a situation of under-budgeting and delays. Even brilliantly planned estimates can have wrong measurements if the labor force is not sufficient. My experience tells me that to foster flexibility into these estimates is helpful. However, it is not a small matter and still requires effort. How do you manage labor shortages in the estimation process? Let's bring about some change of practice - I'd love to hear your ideas or methods that you have used.