Longest Path Overview
Identify the longest possible path between a task and a Finish task milestone on the Hand-offs page. This path calculation takes into account all possible task deviations identified for a work phase during pull planning. Show details for the longest path to view its duration in days, and then highlight or hide the path in the Hand-offs diagram.
Understanding pull planning is key to understanding the benefits of identifying the longest path. In this type of planning, the sequence of work is determined by responsible parties planning backward from a task milestone or goal. Performers request or pull work from their dependencies based on demand for subsequent work to begin and after all prerequisite tasks have been completed. These task dependencies can cause deviations, which makes it difficult to quickly identify the potential impact to a project's schedule. The longest path enables you to compare all possible paths across levels and groups of tasks on the Hand-offs page, and to note the absolute longest duration. Planners can use this information to ensure that all work that needs to be done fits within the project schedule.
The longest path will continue to update based on the following factors as work on tasks progresses:
- Changing task duration
- Changing lag on a hand-off
- Adding or removing hand-offs
- Adding or deleting a task
- Changing an attribute assignment on a task being used for Plan By
In order to calculate the longest path between two milestones, you must first identify at least one Finish milestone, and connect it to the chain using hand-offs without adding successors. If there are multiple Finish milestones, then the longest path of all Finish milestones is used. To view all Finish milestones, select the More Milestones link. If a Finish milestone has no linked tasks, its duration will be zero.
Plan By view settings determine how items are grouped for display on the Hand-offs page. To see tasks grouped by common Plan By options, add and apply them to a view from the 
Settings menu on the page. Display settings for the longest path save by user by page view and are independent from named view settings.
When the longest path is highlighted, task information within the longest path can still be edited but tasks in other paths are not editable. You cannot add or delete tasks or hand-offs while modifying tasks within the longest path.
In some cases, named and quick filters can prevent the longest path from being shown. Adjust filters to display the longest path.