The work you have in the current period of performance, the higher the entropy of the project. Adjust the work load to match the energy available to mange that work load. This means there must be sufficient cost and schedule margin to absorb the variations in the work process. This means the "capacity for work" must be known to some level of confidence before starting the current period of performance.
The period of performance can be an iteration, a rolling wave, a print, or any bounded period of time in which ALL the planned deliverables are delivered.
Boltzmann aid it already...
Entropy = (an adjustment constant) * log of the Work