What are some of the PERT/critical path approach's drawbacks?

Critical path activities are given a lot of emphasis in PERT/CPM management. This can entail paying too much attention to them and not enough attention to other tasks. They can still come in on time even if they have some slack. Furthermore, time estimates are subjective. Even if they used a nifty formula, there will be significant variation in the actual time it takes to perform tasks. Keeping track of time estimates and recalculating the critical path and other metrics on a regular basis can also be time consuming. PERT/CPM appears to be popular among project management instructors and manuals. In certain cases, the effort and attention to detail required will not result in a significant incremental improvement in your project processes. A lot of it relies on whether or not your project is the type where discrete tasks can be accurately estimated individually.