Manual vs Automatic Scheduling of Tasks

In Microsoft Project 2010 and 2013 it is possible to differentiate between Automatic and Manually scheduled tasks.With Automatically scheduled tasks the scheduling engine behaves exactly as it has always done; delaying the Finish date of a task will cause all Successor tasks to be delayed.

However, with Manually scheduled tasks there is no impact on a manually scheduled Successor task until the Project Manager chooses to “Respect Links” for that task.

Having recently taken, and passed the latest Microsoft exams; 74-343 and 74-344, I wanted to revisit some of the basic Project techniques including scheduling. A couple of interesting items popped up.

According to the Microsoft Project 2010 Step by Step book:

“it’s preferable to link the summary tasks to better reflect the sequential nature of the two phases”

That’s fine if all the tasks and phases are automatically scheduled, but if there is a mix, and particularly if the phases are automatic but the tasks are manual then it could lead to additional confusion since tasks may be delayed without impacting successor phases.

Task A3 has been extended, pushing out A4, but since the phases are linked and not the tasks, this has had no impact on Task B1.

If the tasks are linked then, using Respect Links, all successor tasks are pushed out.

Manual vs Automatic Milestones

This study of manually and automatically scheduled tasks prompted me to look at some milestones, and I saw something very odd. To test this I created a very simple plan:

I created a project that starts on a Monday

There is an automatically scheduled task of duration 5 days, that is predecessor for an automatically scheduled milestone (0 days).

There is a manually scheduled task of duration 5 days, that is predecessor for a manually scheduled milestone (0 days).

In theory, with the two five day tasks starting on the same Monday that the project starts, the two milestones should finish on the same day, shouldn’t they?

This is what happens:

The automatically scheduled milestone finishes on the Friday afternoon, but the manually scheduled milestone is pushed forward to Monday morning.

I’ve yet to understand why.