Duration Types in Primavera P6

Duration Type is a setting which allows the user to control how the duration, resource units, and resource units/time are synchronized for activities, so that

the following equation is always true:

If the activity is not started, the names of the values are : Original Duration x Budgeted Units/Time = Budgeted Units

If the activity has started, the names of the values are : Remaining Duration x Remaining Units/Time = Remaining Units

The following table lists the value that changes to balance the equation

Duration x Units/Time = Units

The following table illustrates how the variables in the above equation changes when you change one among them in each of the Activity duration types.

Duration Type When You Change

Duration, what

changes?

When you change

units/time,

what changes?

When you change

units, what

changes?

When you add a

resource, what

changes?

Fixed Units/Time Units Duration Duration Duration

Fixed Duration

and Units/Time

Units Units Units/Time Units

Fixed Units Units/Time Duration Duration Duration

Fixed Duration

and Units

Units/Time Units Units/Time Units/Time

Table 1. Activity duration types

Original, Remaining or Planned Duration = (Budgeted, Remaining or Planned Units) / (Budgeted, Remaining or Planned Units/Time)

The duration type is set at the Project Details level for the Project, but can be modified per activity. Your organization’s project

needs will help to determine which duration type to use. We’ll be discussing in the following section as of what situation forces you to

choose a particular Duration type.

As a hint, if you are adding resources to activities and you do NOT want P6 to recalculate the existing resources units, duration and

units/time, go to Edit, User Preferences from the Menu bar, select the Calculations tab and select the Preserve the Units, Duration and

Units/Time for existing assignments radio button.

Example:-

Now let us consider a Case and work on it to get a better understanding on the Activity duration types.

Given Case :Consider a software company where a resource is assigned design work of a particular website. It is estimated that the design

work would be completed within 5 working days of the resource. The particular resource has a regular shift duration of 8 hours /day.

Find what happens to values of the Original duration, budgeted units/time and Budgeted units when

i. Original duration changes to 10 days

ii. Budgeted units/time changes to 10hours/day

iii. Budgeted units of work changes to 20 hours In each of the activity duration types.

Findings: Original Duration =5 days ,

Budgeted units/time = 8h/d

From the formula we know Budgeted units = Original Duration X Budgeted units/time = 8 x 5 = 40 hours

Type I :-Fixed Units / Time

Units/time for the resources remains fixed; Even when activity duration or budgeted units changes. Used when resources with

productivity output per time period is fixed. Mostly used when Activity type is Resource Dependent. This option is selected if your

organization is concerned with leveling resources and you assign resources specific hours per day on activities.

Original Duration = Budgeted Units / Budgeted Units/Time

Duration Type When You Change Duration,

what

changes?

When you change units/time,

what changes?

When you change units, what

changes?

Fixed Units/Time Units Duration Duration

Table 1.1.1 Fixes Units / Time

Coming back to our case

Where Original Duration =5 days ; Budgeted units/time = 8h/d And Budgeted units = 40 hours.

i.e. Original Duration = units / (units/time) 5= 40 / 8

We were asked to analyze what would happen if

Table 1.1.2 Fixes Units / Time Workout

Changes made (i) Original Duration Changes

from 5 to 10 days

(ii) Units / time changes

from 8 to 10

(iii) Units changes

from 40 to 20

Values changed

Budgeted

units

Budgeted

units/time

Original

Duration

Budgeted

units

Original

Duration

Budgeted

units/time

80h 8h/d 4d 40h 2.5d 8h/d

Original

duration =>

(Units )/

(Units/time) 10=> 80/8 4 => 40/10 2.5 => 20/8

Type II: Fixed Duration & Units/Time

Activity duration and units / time remains fixed; even if remaining unit’s changes. Mostly used when Activity type is Task Dependent

Activity. Organizations which have the project deadline fixed and is also concerned with leveling resources used this activity duration type.

Organization may consider increasing number of resources to keep the resources leveled. Since this activity is Task dependant and activity

duration type is fixed duration & Units/time there would be no layoff in duration time.

Original Duration = Budgeted Units / Budgeted Units/Time

Duration Type When You Change Duration,

what

changes?

When you change units/time,

what changes?

When you change units, what

changes?

Fixed Duration and

Units/Time

Units Units Units/Time

Table 1.2.1 Fixed Duration & Units/Time

Given Original Duration =5 days ; Budgeted units/time = 8h/d And Budgeted units = 40 hours.

Table 1.2.2 Fixed Duration & Units/Time Workout

Changes made (i) Original Duration Changes

from 5 to 10 days

(ii) Units / time changes from

8 to 10

(iii) Units changes

from 40 to 20

Values changed

Budgeted

units

Budgeted

units/time

Original

Duration

Budgeted

units

Original

Duration

Budgeted

units/time

80h 8h/d 5d 50h 5d 4h/d

Original

duration =>

(Units )/

(Units/time) 10=> 80/8 5 => 50/10 5 => 20/4*

Type III :-Fixed Units

This duration type is chosen if you want the activity units to be fixed even when duration or resource units per time changes. Total

amount of Work is fixed. Used when Activity type is Resource Dependent Activities. Unlike previous Duration types increasing resources

decreases the activity duration. Generally used when you have resource under contract basis and you have X units of work to get to be done

from that particular resource.

Original Duration = Budgeted Units / Budgeted Units/Time

Duration Type When You Change Duration,

what

changes?

When you change units/time,

what changes?

When you change units, what

changes?

Fixed Units Units/Time Duration Duration

Table 1.3.1 Fixed Units

Given Original Duration =5 days ; Budgeted units/time = 8h/d And Budgeted units = 40 hours.

Table 1.3.2 Fixed Units Workout

Type IV :-Fixed Duration & Units

Activity duration and Units to remain constant even when the units/time changes. Mostly used when time period and the total

amount of work are fixed. Used when Activity type is Task Dependent Activities. Rate at which a resource can work on the activity can be

changed. You could use this if your organization is more concerned about coming in on the schedule date and within the costs (which are

usually associated with the units)

Original Duration = Budgeted Units / Budgeted Units/Time

Changes made (i) Original Duration Changes

from 5 to 10 days

(ii) Units / time changes from

8 to 10

(iii) Units changes

from 40 to 20

Values changed

Budgeted

units

Budgeted

units/time

Original

Duration

Budgeted

units

Original

Duration

Budgeted

units/time

40h 4h/d 4d 40h 2.5d 8h/d

Original

duration =>

(Units )/

(Units/time) 10=> 40/4 4 => 40/4 2.5 => 20/8

Duration Type When You Change Duration,

what

changes?

When you change units/time,

what changes?

When you change units, what

changes?

Fixed Duration and Units Units/Time Units Units/Time

Table 1.4.1 Fixed Duration & Units

Given Original Duration =5 days ; Budgeted units/time = 8h/d And Budgeted units = 40 hours.

Table 1.4.2 Fixed Duration & Units Workout

Changes made (i) Original Duration Changes

from 5 to 10 days

(ii) Units / time changes from

8 to 10

(iii) Units changes

from 40 to 20

Values changed

Budgeted

units

Budgeted

units/time

Original

Duration

Budgeted

units

Original

Duration

Budgeted

units/time

40h 4h/d 5 50 5d 4h/d

Original

duration =>

(Units )/

(Units/time) 10=> 40/4 5 => 50/5* 5 => 20/4

Summary

Given Original Duration 5days; Budgeted Units 40hours; Budgeted Units/ time 8hours/day. The following table summarizes as of what

happens to the variables in each of the activity duration types.

Du

rati

on

Typ

e

Original Duration Changes from 5 to 10 Units / time changes from 8 to 10 Units changes from 40 to 20

Budgeted units

(Or. Val:- 40h)

Budgeted

units/time(Or. Val:-

8h/d)

Original Duration

(Or. Val:- 5d)

Budgeted units

(Or. Val:- 40h)

Original Duration

(Or. Val:- 5d)

Budgeted

units/time

(Or. Val:- 8h/d)

Fixed Units / Time 80h 8h/d 4d 40h 2.5d 8h/d

Fixed Duration &

Units/Time 80h 8h/d 5d 50h 5d 4h/d*

Fixed Units 40h 4h/d 4d 40h 2.5d 8h/d

Fixed Duration & Units 40h 4h/d 5d 50h* 5d 4h/d

Table 2: Activity duration table chart

Or.Val - Original Value * - in certain cases original duration remains fixed and the other fixed variable is forced to changed. Reference:-

https://ccsspl123-public.sharepoint.com/Support%20Documents/duration%20types-Activity.pdf

http://www.projectcontrolsonline.com/Forum/tabid/65/forumid/13/threadid/529/scope/posts/Default.aspx