Pete Kolevas, PMP

I am an advocate of not assigning multiple resources to a task in MS project if possible.  Assigning only one resource to a task simplifies the way in which MS Project calculates the amount of work.  However, I can understand that some people want to use this functionality, especially for very large efforts, so the following post is to provide the fundamentals to assist in this regard.

There would be 2 ways to plan this out in MS Project.

Scenario:  I have 2 leads that are responsible for providing detailed work plans to their teams.  As a project manager I want to manage a task to make sure these work plans are planned and completed on time.  I have a development lead and a QA lead that are responsible for this work.

The first way and my preferred mechanism would be to create 2 tasks called “Create Work Plans” and assign the development lead to one task and the QA lead to the other.  In this scenario, I can deal with them as 2 distinct entities.  Once this is complete you can review my earlier on post on “Basic Scheduling calculation in MS Project” and you will be on your way to a simple schedule.

The second way becomes more complicated.  We can proceed with assigning both resources to one task. This requires some additional knowledge and setup of how MS Project works.

• Performing these  steps to help get you started.
• Setup the Gantt Entry table and view for easy entry. (Add the work column)
• Split the view, and enable any one of the sub views that has the resource work displaying.  I personally like the Resources and Predecessor view

Now what you have done is enabled the screen to show you all the options you need in order to understand what MS Project is trying to do for you.  Look at the screen shot below and you will see all the places you will have to review in order to move forward.

The next items to understand in order to be successful at assigning multiple resources to a task in MS project are the ‘Task Type” and “Effort Driven” flags.  These are important to understand when assigning a single resource, but become must have knowledge when working with multiple resources. Below are the multiple combinations that can be set on a single task.

• Fixed Work with Effort Driven enabled
• Fixed Duration
• Fixed Duration with Effort Driven enabled
• Fixed Unit
• Fixed Unit with Effort Driven enabled

When the effort driven checkbox is enabled, MS Project assumes you are going to split the work evenly on the tasks depending on the number or resources you assign.  Take an example where you have a fixed work task, with 16 hours of effort and 2 days duration.  You assign 2 resources to the task and MS project will place 8 hours of work on each resource.  Give it a try and watch what happens in the lower window.

Fixed work, Fixed Duration, and Fixed unit task types with the effort driven flag enabled will all act in a similar manner.  I recommend practicing with these until you understand what is happening; just remember to set the work and duration numbers back to their original starting points. (Also use the resource dialog box to assign and remove resources from tasks when practicing   ).  You will become an expert in no time.

Once you get good at the above simple scenario, try a fixed duration task using an odd number for work such as 17 or 21 hours over 2 days, something that does not divide by the 2 resources evenly.  Then try assigning these resources one at time to the task as well as at the same time from the resource dialog box.  Observe the calculation performed.  MS project is trying to be helpful.  Fixed duration with effort driven turn on is difficult to work with.  I would recommend turning effort driven off for these types of tasks.

My next post will include more examples and scenarios for turning off the effort driven flag, but now that you know how to practice, feel free to try it for yourself.

Microsoft Project has 3 main factors that go into the scheduling criteria of a task.

1.  Duration

2.  Work

3.  Unit (% of an allocated resource)

In an attempt to assist the Project Manager, the software will work to automatically calculate one of these factors based off of the default settings and the way in which a PM enters the information.  The way in which to think about this is the following: 

• One of these factors is fixed and will remain constant.  The default setting is fixed Units (why that is I have no idea).  I recommend you change this and will tell you how to change this a little later.
• You will then need to place the other 2 factors in manually.  Whatever the third factor is, Microsoft will automatically calculate it.  

I recommend until you understand the following examples and play with them you only assign one resource to a task.  Once you get good at this, you can progress to multiple resources on single task.

Example 1:  Lets assume you have the default setting set to fixed work.  That means once you type in the work number Microsoft project will not attempt to automatically calculate for you.  You type in 16 hours of work.  Next you assign a resource at 100% units of allocation.  Microsoft will automatically calculate the third criteria which in this case is duration.  Assuming an 8 hour work day, the system calculates 2 days duration.  Easy right?

Example 2:  Next let’s take the same example and change the units of the allocation to 50% units of allocation.  What will Microsoft recalculate?  Yep  Duration.  The system calculates 4 days duration.

Once you understand this fundamental calculation your life becomes much easier in Microsoft Project.

How to set the default fixed criteria:

1.  To set the default task type criteria for all tasks in the project, go to Tools>>Options>>Schedule Tab.  Under the “Default Task Type” drop down select the criteria you would like to fix.  Please note: this only works for new tasks entered in the plan.  If you have a number of tasks already in the plan please review #2.

2.  To set the default task type criteria for a single tasks in the project, double click on the task>>select the advanced tab>>Select the Task Type criteria you would like to fix for this particular task.  You can also change the task type on multiple tasks by selecting those tasks in the plan, then selecting Project Menu>>Task information>>Click on the advanced tab and change the task type.

Hope this makes your life easier in MS Project. 

Understanding the critical path in MS project can be a relatively daunting task.  In order to do this you need to have a fundamental understanding of the predecessor relationships you have setup on the tasks within the plan.

First thing to do when determining the critical path on the project is to ensure that every task in the project has a predecessor, with the exception of summary tasks and the first task in the project.  To do this determine the mandatory logic throughout the project first, and then move into your discretionary logic.  Once complete you will have a plan that you can work with to understand the critical path.
In order to view the critical path in MS Project I recommend doing 2 things:

• Display the critical path on the Gantt chart.

1. Right click on the open space in the Gantt Chart.
2. Select Gantt Chart Wizard.
3. Move through the wizard selecting the critical path options.

• Display the Total Slack column on the Gantt table.

Once complete, any task with 0 days in the Total Slack column is considered critical since it has no slack or ability to slip until it impacts the end date of your project.  All the tasks with 0 slack on them should also be red in the Gantt chart.

Any task with a number >0 should be blue on the Gantt chart and for the purposes of MS Project is considered not critical.

Now there are a few things to review since the critical path is exposed.

• Does your discretionary logic make sense?  Do you have too many dependencies on tasks due to this logic?  If so tweak the plan.
• Does your discretionary logic cause too many tasks to become critical?  Should you rearrange some logic to make the critical path make more sense?  If so tweak the plan.
• Are there any tasks with large amounts of time in the Total Slack Column?  If so, is the logic on that task appropriate, or did you miss that task when creating the logical network.  If so tweak the plan.

Once you have reviewed and are comfortable with the schedule network you can manipulate the way in which MS Project shows the critical path.  First why would you do this?

• An example would be that there are a few tasks that are not critical but only have 1 or 2 days of slack.  You may want to show these tasks as critical to management.
• Another example would be tasks that are near critical above, but have resource constraints that make you concerned such as a key resource that may leave.
• A third example would be to influence behavior for a resource on that task.  Once a resource realizes their task is not on the critical path, they tend to think they have more time and begin to procrastinate.  Procrastination on a task that has slack will eventually eat that slack and steal it from other tasks.  This is what I like to call “Stealing Float”  ex.  Testers hate it when developers steal the float and they end up with no slack to test.

To manipulate the way in which MS project calculates the critical path, open the Tools>>Options menu, click on the Calculation tab, and increase the number of days in the option “Tasks are critical if tasks are less than or equal to”.  When you move back to the Gantt chart tasks that meet this criterion will now be red and considered critical to MS Project.

Feel free to post any questions or comments