Depending on the complexity of the plans and the dependencies between activities, you absolutely can go over a planned date, so long as it's the early start. In

Depending on the complexity of the plans and the dependencies between activities, you absolutely can go over a planned date, so long as it's the early start. In critical path method scheduling, you will typically show an "early start" and "late finish" dates for an activity and maintain float to the early or late start of the next (driven by other activities in the DAG and availability of resources assigned to them). I (and others) like to explicitly state contingency factors and/or risks as successor activities that consume this float. They can also be used for Monte Carlo analysis where those activities are randomly increased in duration (usually on some statistical curve as discussed in the article) What we are really doing is simulating many many permutations of the effects of known risk likelihoods and consequences across the graph. Otherwise in a large program of works we will tell Project Managers or Contractors that they can manage their own float which gives them flexibility to execute. Another method that simplifies this is PERT[1] method, where you take, optimistic, pessimistic and normal durations to produce an expected duration. [1]https://en.wikipedia.org/wiki/Program_evaluation_and_review_technique#Time https://en.wikipedia.org/wiki/Program_evaluation_and_review_...