Constraints - an introduction

Constraints, what is it again? Here a quick and easy recap about constraints in MS Project: A constraint is a restriction given to a task or milestone. Examples are:
  • This task cannot start earlier than July 1, 2016
  • This task cannot finish later than August 23, 2016
  • This task must start on January 1, 2017
Using constraints, you can control the start or finish dates of important tasks. It is a useful tool to be able to easily reschedule the project because when you put a constraint on a task in a linked network of tasks, it will effect the whole chain of tasks. MS Project automatically assigns the As Soon As Possible constraint (which actually is not a restriction) when you enter a task (when planning from start date). You should set other constraints only when necessary, because:
  • Constraints will usually decrease the level of schedule flexibility of tasks
  • As the amount of task flexibility decreases also the amount of dynamic behavior of the schedule gets lost

Check your constraints

At various stages in your project, you may want to check the constraints on tasks in your schedule, particularly the tasks on the critical path, to make sure they are necessary. For each unnecessary constraint you add 6 manual actions for keeping the schedule up-to-date! Limiting to only the necessary constraints will keep your schedule as dynamic as possible. Read the article 'how to create constraints' to learn more about that topic.
Back to blog