Thanks for posting on this one Therese, I remember seeing it back in the day and thinking "huh: I should learn more about Critical Path." Then a squirrel ran past my window, and...well, you can guess the rest. Especially because a new client and I had a "float" debate this week (remind me to tell you about "Crumple Zone" at LEAP), off into help.workfront.com I went tonight. Here's what I learned : "https://support.workfront.com/hc/en-us/articles/216606638-Understanding-the-Critical-Path">Understanding Critical Path asserts:
Taking these features into consideration, the system calculates the Critical Path by using the longest path between the earliest task and the task that determines the end of the project. The Critical Path Calculation takes into account what is the earliest and latest time that each task can start and finish by without making the project longer. This process determines which tasks are "critical" (and belong to the longest path) and which ones have "total float" (can be delayed without making the project longer). Any delay in the activity of a task on the Critical Path directly impacts the Planned Completion Date of the project (there is no float on the critical path).
So to me, any Task which if delayed or stretched would impact the Project's completion date would by definition be a Critical Task, and on the Critical Path. "https://support.workfront.com/hc/en-us/articles/216636478-Understanding-the-Slack-Date-of-a-Task">Understanding the Slack Date asserts:
The Slack Date displays the exact date when a task could definitely impact the Completion Date of the project. The Slack Date is different than the Projected Completion Date, as the predecessor relationships and task constraints increase the slack time. For tasks that are on the Critical Path of the project, the Slack Date matches the Projected Completion Date of the task unless the Progress Status of the task is already Late or Behind.
Not (as I recall) ever having added the Slack Date to a view before, I did so (along with the Projected Completion Date and Is Critical built in parameter), then created a very simple Project starting next Monday (i.e. in the future) at 8am (i.e. the beginning of the Work Day, according to my 8 hour per day Workfront Default Schedule), with with three Tasks:
Task 1, ASAP, 1 Hour
Task 2, ASAP, 1 Hour, with a Predecessor of 1fs (so, Task 1 "pushes")
Task 3, ASAP, 1 Hour
The results in the view made sense:
Task 1 Projected Completion Date (9am), Is Critical = True
Task 2 Projected Completion Date (10am), Is Critical = True
Task 3 Projected Completion Date (9am), Is Critical = False
I then bumped up Task 3 by half an hour, and again, the results made sense to me:
Task 1 Projected Completion Date (9am), Is Critical = True
Task 2 Projected Completion Date (10am), Is Critical = True
Task 3 Projected Completion Date ( 9:30am ), Is Critical = False
I then moved Task 3 up to two hours, matching the sum of Task 1 and Task 2, and the results in the view made sense; both paths became critical:
Task 1 Projected Completion Date (9am), Is Critical = True
Task 2 Projected Completion Date (10am), Is Critical = True
Task 3 Projected Completion Date ( 10am ), Is Critical = True
Penultimately, I set Task 3 to three hours, exceeding the sum of Task 1 and Task 2, and something interesting didn't happen -- the 1 and 2 path stayed Critical:
Task 1 Projected Completion Date (9am), Is Critical = True
Task 2 Projected Completion Date (10am), Is Critical = True
Task 3 Projected Completion Date ( 11am ), Is Critical = True
Finally, I recalultated the timeline, and then things aligned as I expected:
Task 1 Projected Completion Date (9am), Is Critical = False
Task 2 Projected Completion Date (10am), Is Critical = False
Task 3 Projected Completion Date (11am), Is Critical = True
That told me that until the timeline is recalculated, the Critical Path could be "stale":
Never being one to not try the unobvious (or use quatruple negatives to convolute a thought), I then shortened Task 3 back to 1 hour, and was not surprised...until I thought about the ramifications for reporting:
Task 1 Projected Completion Date (9am), Is Critical = False
Task 2 Projected Completion Date (10am), Is Critical = False
Task 3 Projected Completion Date ( 9am ), Is Critical = False
So: that demonstrates that it is possible to have a Project with NO Critical Path shown (albeit temporarily, until the timeline recalculates). The punchline? FOR BEST RESULTS, RECALC TIMELINES EARLY AND OFTEN. As an aside, at this point, you might want to consider:
refreshing your memory on how Timelines get "https://support.workfront.com/hc/en-us/articles/217240367-Recalculating-Timelines-for-Projects">automatically or manually calculated; and
using our "http://store.atappstore.com/product/recalc-helper/">Recalc Helper solution to perform manual recalculations of Custom Data, Finances, or Timelines using a filter; and
using our "http://store.atappstore.com/product/force-timeline-recalculation/">Force Timeline Recalculation to do likewise, but also on a Scheduled basis (e.g. in addition to the "nightlies")
Along the way, I also made one other interesting observation -- the Slack Date is (as it's named, so presumably As Designed) a DATE, which I proved by switching its column in my view to text mode and using this to reveal its underlying "always midnight" aspect:
valuefield=slackDate
linkedname=direct
valueformat= longAtDate
displayname=
namekey=slackDate
textmode=true
querysort=slackDate
Recalling waaaaaay back up again, since:
" The Slack Date displays the exact date when a task could definitely impact the Completion Date of the project."
I suspect there are scenarios (untested) where the DATETIME nature of the Projected Date and DATE nature of the Slack Date could conflict in a manner that gives unexpected results from an "Is Critical" perspective.
I will leave the latter for the next Adventure Ranger to scout through. Regards, Doug Doug Den Hoed - AtAppStore Got Skills? Lend a hand!
https://community.workfront.com/participate/unanswered-threads -------------
