Woody's PROJECT Watch

Q: I have an employee who changes his work shift every 6 weeks,  alternating between a regular day shift and an evening shift.  I tried changing his calendar to evening  working times when he starts working evenings, but that also changed the schedule when he's supposed to be working the day shift.  Is there an easy way to get an accurate schedule in this case? - Dave T.

A: Well, "easy" is a relative term. The only way to handle this schedule accurately is to go through your employee's resource calendar and change the working times to evening hours for those dates when he's on the evening shift. It's a little tedious getting it set up, but as long as he stays on the schedule and you don't have to constantly modify his calendar to accommodate unanticipated changes then it should be worth the effort.

Q:We record several "milestones" for the project phases (summary tasks) in our projects. For example, we record the date the phase was proposed to the client and the date it was approved. We put these dates in custom date fields, but I'm having trouble calculating the number of working days that lapse between the two dates (how long it took to get approval). How do you do that?  Jon P.

A:This is easy to do starting with Project 2000. You just use a custom Duration field to calculate the difference between two dates. There is a special function that does this (the ProjDateDiff function) and it also looks at the calendar to determine how many days between the two dates are working days. By default it uses the project calendar (the one you have defined for the project in the Project Information dialog box); but you can instruct it to use a different calendar to determine the working days if you want.

Assume you have placed the earlier date in the Date1 field and the later date in the Date2 field. Follow these steps to set up the calculation in the Duration1 field::

1. Insert the Duration1 field in the table where you enter the custom dates.

2. Right-click on the field title and choose Customize Fields. The Customize Fields dialog box will open with the Duration1 field selected for editing.

3. Click the Formula button to open the formula editing dialog box.

4. Enter the following formula: 
   
                    ProjDateDiff ( [date1], [date2] )
   
   Note that the earlier date is listed first, then the later date.

5. Click OK to close the editing box.

6. To enable summary tasks to use the formula, go to the section labeled Calculation for Task and Group Summary Rows and select Use Formula.

7. Click OK to close the dialog box.

If you want to use another calendar for calculating working days instead of the project calendar, add the name of that calendar at the end of the formula in quotes. For example, if the calendar you want to use is named My Calendar the formula would look like this:

                      ProjDateDiff ( [date1], [date2], "My Calendar" )
This will work fine for tasks that have dates entered in the custom date fields used in the formula. But, if a task has NA in either of the fields then the Duration1 field will display #ERROR for that task. That looks a little messy, and if it really bothers you then you might use a custom Text field instead and have it display a blank if either date is NA. However, that's a messy formula and explaining it is beyond the scope of today's issue of Project Watch.  I'll show that in our next issue.