HELP with updating Issues - predecessor complete but remaining duration doesn't calc. from the DD

glad I could help sometimes you have to go very far back to find the culprit pushing thru the completed activity. 

I have written a paper on this and have posted here at Planning Planet in the library. It gives you several way on how to track down the driver. 

here is the link 

http://www.planningplanet.com/guild/library/cpm-scheduling-driving-thro…

Finding why and where there is Out-Of-Sequence progress is easy, look for broken links.  Merely knowing that an activity is out-of-sequence is not good enough, a report that only lists out-of-sequence activities is not good enough.

It would be insane if on a thousand activities, thousand links schedule you look for broken links following one by one the links and calculating remaining lag taking into consideration lag calendar, let the computer do the math.

Extended Relationship Database System

• Remaining Lags - We plan to build in a function to calculate and display Remaining Lag.  Currently, the data field known as, “Lag” actually represents “Original Lag.”  It does not reflect the amount of lag remaining to be used.  This is especially problematic for lags that are currently crossing the data date.  These lags are neither at 0 days, nor are that at their original setting.  You cannot calculate an in-progress schedule without knowing Remaining Lag.  The original CPM did not have Remaining Duration, only (Original) Duration.  It is time for CPM to include Remaining Lag. 

In the following example predecessor activity is finished but there is still some remaining lag that is broken.  Think of lag as an activity who represent elapsed time and that is calculated automatically.

Once you know the broken link you might still need to know elapsed and remaining lag to fix logic.

If using hammocks or if using formulas and a script you can calculate Remaining Lag but it is somewhat complicated. 

I agree with Ron Winter, it is time for CPM to include Remaining Lag.

first problem is that you have out of sequence progress

here is an example

activity A,B,C & D all tied finish to start

activity A is complete

activity B has started but 2 days are remaining

activity C is completed

activity D has started but has 5 days remaining

you are using retained logic so it is honoring the logic whihc means that 

The remaining 5 days for activity D CAN NOT START unitl the remaining 2 days for activity B have been completed

This means that the logic from activity B is PUSHING THROUGH activity C (which is competed) preventing the REMAINING duration for activity D to begin.

Second problem go to view bars then highlight the actual work row in the 3rd column chnage the time scale to current bar . that will fill the gap that  is showing. 

Check your schedule log for Out of sequence activities. Even if all of the activity's predecessors have been completed, if one of the predeccessor's predeccesors has not been, then this can cause the issue you describe.

Other possible reasons are calendar issues, and external constraints.

1. Do the links between the activities have remaining lag?
2. Does your software provide information about such out-of-sequence occurrences?  Software such as Spider Project identifies them under the links table as Broken Links.

HANDLING OUT-OF-SEQUENCE PROGRESS

Making CPM More Transparent

• In-Progress Lag Report and Value:  Remaining Lag should be displayed just as remaining duration is shown and editable.  The CPM feature of Remaining Duration was added so that Schedulers could monitor and change this calculated duration result.  Lags are to relationships what durations are to activities.  Why should Remaining Lag calculations be discarded by the software instead of saved and displayed?  Why should we be unable to indicate that actual remaining lag is only 2 days instead of the calculated 4 days?  Part of the reason CPM Schedules are so hard to understand is that fact that not all of the data used is displayed.

Good Luck.