Types of activities are very important to understand. These types determine how the activity start and finish will be calculated. There are 6 types of activities in Primevara P6.
- Task Dependent
- Resource Dependent
- Start Milestone
- Finish Milestone
- Level of Effort
- WBS Summary
Task dependent activity is an activity which uses activity calendar to calculate start and finish dates. This type of activity is not dependent on any resource calendars. So, even if you assign one or more resources to this activity, start and finish dates will still be calculated from activity calendar. Task dependent activity is most commonly used activity type in project scheduling.
In the picture below, an activity has a type of task dependent and it is assigned a 7 days calendar. Activity starts on 01-Jan-17 (Sunday) and after consuming 10 days of assigned calendar, it finishes on 10-Jan-17 (Tuesday). Even if resources are added to this activity, the start and end dates will not be changed.
Resource dependent activity is an activity which uses resource calendar to calculate start and finish dates. Activity calendar will not be used unless there are no resources assigned to that activity. For example, if excavation in foundations is assigned a 7 days calendar but the excavator which has to do the excavations is available only 5 days a week then start and finish dates of this activity will be calculated from 5 days calendar (if the activity type is resource dependent). In case there are more than 1 resource assigned to a resource dependent activity, primary resource calendar will be used in calculations.
In the picture below, an activity has a type of task dependent and it is assigned a 7 days calendar. This activity has also a resource assigned to it which has 5 days calendar and it will not work on Saturday and Sunday. However, activity type is still task dependent. Note that activity starts on 01-Jan-17 (Sunday) and after consuming 10 days, it finishes on 10-Jan-17 (Tuesday).
If we look at resource usage profile, note that the assigned resource will work 8 hours a day from Sunday, 1-Jan to Tuesday, 10-Jan. As the resource has its Saturday and Sunday off in its calendar, these days are shown as red or over allocated units of the resource. This means that by keeping the activity type as task dependent, we are forcing the assigned resource to use the activity calendar.
Now if we change the activity type to resource dependent, note that original duration is changed to 12 days and activity will now start on 02-Jan-17 (Monday) and after consuming 10 days of assigned resource, it will finish on 13-Jan-17 (Friday).
If we look at resource usage profile now, note that the assigned resource will work 8 hours a day from Monday, 2-Jan to Friday, 13-Jan. As the resource has its Saturday and Sunday off in its calendar, these days are shown as blank days and the resource will not work on these days. Further note that resource will actually work on 10 days as you can see 10 number of bars in the profile, however these 10 days will actually take 12 days of the activity calendar.
Start Milestone is a type of activity which represents start of some major event or important series of tasks. For example, start of the project, start of foundation works, start of structure works etc. Start Milestone has only start date and it has no finish date. Also the duration of a Start Milestone is zero. This milestone together with finish milestone is used to show summary of project schedule. For example if you have more than 1000 activities in a schedule and you are given a task to show schedule summary, you can only report the milestones which will show start and end dates of important events of your schedule.
In the example below, ‘Start of Electrical Works’ is a Start Milestone as it has only the start date. It is represented by a black diamond in the Gantt chart.
Finish Milestone is a type of activity which represents finish of some major event or important series of tasks. For example, finish of foundation works, finish of structure works, finish of the project etc. Finish Milestone has only Finish date and it has no Start date. Also the duration of a Finish Milestone is zero. This milestone together with start milestone is used to show summary of project schedule. For example if you have more than 1000 activities in a schedule and you are given a task to show schedule summary, you can only report the milestones which will show start and end dates of important events of your schedule.
In the example above, ‘Finish of Electrical Works’ is a Finish Milestone as it has only the finish date. It is represented by a black diamond in the Gantt chart.
Level of Effort:
Sometimes, there are activities in schedule whose duration is dependent on some other activities. For example, project management activities start as the project is started and finish when the project is finished. Note that duration of project is not fixed. In planning stage, you have to do number of iterations to reach at optimum schedule. For each iteration, you may have to produce cost estimate of the project. So, whatever will be the duration of project, duration of these project management activities will be adjusted accordingly and you will get correct estimates of the project. Well, thats just one example, there are number of cases in which this activity type can be used.
In the example below, you can see that start of ‘Consultancy for Electrical Works’ is connected to ‘Start of Electrical Works’ and finish of this activity is connected to ‘Finish of Electrical Works’. As this activity is a Level of Effort so its duration is dependent on total duration between these two milestones. If duration of activity is changed, then duration of Level of Effort activity will also be changed accordingly.
WBS Summary activity is a type of activity which shows summary data of all activities in a WBS band. You don’t have to give any relationship to this activity type. It automatically calculates the summary data. WBS band also shows summary of activities but the different is that you can assign resources to WBS Summary activity. This helps when you don’t have estimates of activities but you have estimate of the whole work package. You may then use these estimates for top down estimation.
Another use of WBS Summary activity is that if you have some activities in a WBS with different calendars assigned to them then you can use WBS Summary activity and assign a calendar to it from which you want to see summary duration of the whole WBS.
So thats all from this post. Hope you have learned some useful concepts. If so then do comment or subscribe.