Hi,

Let us continue with Slack story in MS PROJECT 2013.

First I will create a new Project with Task List:

Because picture is too big I will show you the Gant Chart:

Now, again I will apply the Detail Gant View:

and:

and I will get:

OK. Let me explain!

Task 1, and Task 2¨are on the Critical Path. On the Critical path if any Activity (Task) is late, the whole Project is late, so in the Critical Path, slack is ZERO!

I will now show you the Free Slack, and the Total Slack fields!

• Task 1, and Task 2 are on the Critical Path, so the Free Slack, and Total Slack are zero
• Task 3 is predecessor of Task 4 and it has Free Slack zero days (because free slack is amount of time that Task can be late without making late his successor), but Total slack is 10 days, because if Task 3 is late 10 days, the Project will still finish on time!
• Task 4 has 10 days of Total Slack, and free slack, because it has no Successor!
• Task 5 has 9 days of Free slack (because Task 6 should start after Task 4, and Task 6 are finished). It has 18 days of Total Slack, and that is obvious, because if it is late up to 18 day, the Project will still be on time!
• Task 6 has 9 days of Total Slack, and free slack, because it has no Successor!
• Task 7 is predecessor of Task 6 and it has Free Slack zero days (because free slack is amount of time that Task can be late without making late his successor), but Total slack is 9 days, because if Task 7 is late 9 days, the Project will still finish on time!
• Task 8 is the same as Task 7

OK. Can Float be negative? Yes it can!

Here is the example:

Now I will put a hard constraint to the Task 3, so it Must Start on January 10, 2013:

and I will get the Warning:

and then:

Finally I will get:

As you can see, because Task 2, and Task 3 has Finish to Start Relationship, and Task 3 must begin one day before Task 2 is finished it has –Slack 1day (negative slack).

Regards,