One main solution to staying on or ahead of schedule (positive schedule variance) is adequate and thorough planning during the initiating and planning phases. During weekly design review meetings, the group will discuss and agree on factors like estimated expenditure, amount of materials needed, timeline/deadline, and spec. If the values are carefully chosen, the product will not require huge adjustments later on. Members can also talk about their progress in the meetings to make sure no one is falling behind schedule.
However, even with careful planning, change requests made still need to be filed. This could be due to potential clients/stakeholders changing their original needs, or validation and verification test failures. Companies may also fail FDA audits by not keeping a record of work logs and appropriate documents for each phase. This can make the schedule variance value negative, since additional time will be required to revisit prior steps.