MS Project: Scenario planning issue

Question

Relatively new to MS Project and have come across an issue, I've searched through threads to see if I could see anything similar without luck, so apologies if this has been covered previously.

The base scenario is that I've produced a high level schedule with activities and durations (in days) without resources or work inputs. A key stakeholder wants to understand scenario planning options.

My base case intention was for 10-hour days, so each entry of 1 day would be equivalent to 10 hours (even though I didn't change the working time in calendars).

My second case is to switch from day shift to night shift which would essentially have the same number of hours, however I wanted to add in 20% contingency. I couldn't figure out a blanket way to attack this, so I just increased all the durations by 20% (i.e. 2 days is now 2.4 days). I don't quite think this worked perfectly, either. (Anyone care to weigh in?)

My third case is working 6-hour days instead of 10-hour days, to determine the impact it has on the final construction completion date.

My hope, misguided as it may be, was that I could have my base plan at 10-hour days (changing a few options and calendars in the base plan), and then simply modify the working hours / calendar to spit out my other scenarios.

If I did change the calendar to 10-hour days, Monday to Friday, the durations for each activity would change from 1 day to 0.8 days. Is there something I need to change in task type, or do I need to re-enter all values? I even tried changing duration to hours and entering 10 hours after modifying calendar and it pushed 1 day activities into the next day ... unsure why.

Any suggestions on how to tackle this in the most appropriate way? Is it possible without assigning resources and work efforts etc?

Answer 1

Microsoft Project has multiple parameters that affect the time. The relevant ones are:

• fixed days or fixed duration or fixed units
• general calendar
• generic / specific resource calendar.
• work hours per week

When you use fixed duration, if you set it to 3 days, it's not going to change when you change the resource allocation.

I think you should use fixed units and define the resource calendar and percent allocation.

Answer 2

A few suggestions. As you are going to be switching the definition of a day you may want to show durations in hours or consider hiding the duration field all together and show only start and finish dates. If you don't have resources assigned you can then enter the work estimates as the duration in hours. The number of hours of duration shouldn't change when you change the number of working hours per day - just the finish dates.

As far a changing working time - think about creating some different calendars and then just apply those calendars as the Project calendar. It will save you having to re-edit the same calendar over and over.

For the 20% contingency - why not just make a night shift calendar with only 8 working hours per day. That will give you the change in finish dates to show the effect of only an 8 hour day or a 20% drop.

I hope this helps.