The number of patients available to join a trial drops by about 90% the day a trial begins. This is often referred to as "Lasagna's Law" and is mitigated by using only inclusion criteria that are definitely required, by reviewing potential enrollees prior to choosing the site investigators and by having a well-developed recruitment strategy.

Phase 4 trials can be monitored less intensively than investigational period trials.

Every biotech and pharmaceutical organization with products in clinical development must have a designated recruitment specialist, either in-house or at the CRO, whose role is to help ensure sufficient enrollment in the trial. Not to do so risks major delays and possibly major issues and problems.

Monitors must understand the intensity and lattitude that is required and they are allowed in their monitoring activities. Sometimes it is only necessary to monitor high enrolling sites or a random group of sites in large trials. In mega-trials it is impossible, and not regulatorily required, to monitor these trials as extensively as pivotal or many other types of trials.