Duration Correlations


Overview

Duration correlations make it possible to relate the sampling of durations between multiple activities.

Correlations are ONLY available between activities, not between hammocks, LOE's, WBS summaries, milestones, or benchmarks.

For example, if the duration of an activity is sampled at the upper end of its range:

  • You may want the duration of another activity to also be sampled at the upper end of its range (positive coefficient)

  • Or you may want the duration of another activity to be sampled at the lower end of its range (negative coefficient)

  • Duration correlations are defined using coefficients from -1 to 1.

Coefficient Behavior

GoalExampleCoefficient
StrongA sampled high, B sampled highHigh positive, e.g. "1"
WeakA sampled high, B sampled somewhat highLow positive, e.g. ".25"
Weak inverseA sampled high, B sampled somewhat lowLow negative, e.g. "-0.25"
Strong inverseA sampled high, B sampled highHigh negative, e.g. "-1"

Tip

Correlations can be defined in P6 and imported. For more info, see Mapping User Defined Fields.

Defining Correlations

  1. Click the Ranging  driver.  

  2. Select an activity from the upper list.

  3. Click the View button above the bottom list and choose Duration Correlations.

  4. Check the box in the Correlate column next to a desired activity in the lower list.

  5. Adjust the value in the Coefficient column as necessary.

Required columns will display a Warning icon. If none of the required columns are visible, they must be turned on (see Customizing Columns). So long as any column contains a warning, the entire row will be colored red.

Tip

At any time, rows with warnings can be found by typing "error" or "warning" into the search box above the list.

Mutual Exclusivity Coefficient Warning

Any coefficient between -1 and 1 is technically valid; however, a single coefficient is always taken in consideration with every other coefficient during simulation. For this reason, it is possible that a single coefficient makes the entire set incalculable. Note, however, that this value by itself is not incorrect and could be accepted if other coefficients were modified. Take the following activities and their coefficients:

Correlation betweenCoefficientOrder defined
A and B11
B and C12
C and A-13

In this case, it is the correlation between C and A at "-1" which causes the entire set to be both positive and negative simultaneously and hence reset; however, if the order entered were 1 then 3 then 2, it is the correlation between B and C that would be invalid. Similarly, if the other coefficients were modified first to also be negative, then no error would arise. 

In addition to positives and negative coefficients, correlations may become incalculable due only to the variance between coefficients themselves.

Copy/Paste/Fill Down

Once entered, correlations can be copied and pasted or filled down to save time. For details, see Interface Tour.

Available Table Columns

For details on customizing columns, filtering, sorting, and organizing by WBS, see Interface Tour.

 Correlation Columns...
ColumnDescription

Abbr. Description

A NetPoint-unique field limited to 48 characters for describing the activity.

Calendar

The schedule that work on the activity can take place.
Codes

A submenu containing one column for every code in the schedule.

The organization and visibility of code columns is NOT saved with the application. Code columns must be turned back on every time the tab is changed.

CoefficientA value from -1 to 1 for specifying the degree of correlation.
Completed DurationThe amount of time already completed.

Constraint #1

The primary constraint, if any. The following abbreviations are used: ALAP (As Late As Possible), MEO (Finish On), MEOA (Finish On Or After), FNL (Finish On Or Before), MS (Mandatory Start), MF (Mandatory Finish), MSO (Start On), SNE (Start On Or After), and MEOB (Start On Or Before).

Constraint #2

The secondary constraint, if any. The following abbreviations are used: ALAP (As Late As Possible), MEO (Finish On), MEOA (Finish On Or After), FNL (Finish On Or Before), MS (Mandatory Start), MF (Mandatory Finish), MSO (Start On), SNE (Start On Or After), and MEOB (Start On Or Before).
Constraint Behavior

A toggle for controlling how constraints behaves during simulation (only enabled if an activity/milestone has a constraint).

If an activity has two constraints and Maintain is chosen, both will be maintained unless one is triggered, in which case the second one will be ignored.

ALAP constraints will never be maintained and this option disabled for activities with only ALAP constraints (if an ALAP and another constraint exist and Maintain is chosen, only the other constraint will be maintained).

CorrelateA checkbox for applying a correlation.

Description

The text field for describing the activity.

This column cannot be removed from the table when organized by WBS.

Distribution TypeA shape for organizing a range of values (e.g. durations, impacts, etc.).

Drift

The amount of the time an activity may advance before advancing the project start.

Duration

The amount of time the activity takes to complete.
Duration CorrelationsA summary of activities that have been correlated by ID with the coefficient showing in parenthesis.
Early FinishThe date the activity completes when its drift is equal to zero.
Early Start

The date the activity begins when its drift is equal to zero.

Existence ProbabilityDuration ranging only. The percent of iterations an activity will occur. When it occurs, the activity's duration is sampled from its range. When it doesn't occur, its duration is zeroed out for that iteration.

Finish Date

The date the activity completes. If actualized, the date is appended with an asterisk ( * ).
FloatThe amount of the time an activity may be delayed before delaying the project completion.
High %A range value used when Trigen is chosen for the distribution type.
IDThe user-entered unique identifier.
Include

A checkbox for enabling or disabling the selected functionality.

This column cannot be removed from the table when organized by WBS.

LambdaA range value used when BetaPert is chosen for the distribution type.
Late FinishThe date the activity completes when its float is equal to zero.
Late StartThe date the activity begins when its float is equal to zero.
LikelihoodFloating only. The percent of iterations an activity’s float will be sampled from its range during floating and pacing.
MaxA range value used for the following distribution types: BetaPert, Triangular, Trigen, and Uniform.
MeanA range value used for the following distribution types: Normal and Log-Normal.
MinA range value used for the following distribution types: BetaPert, Triangular, Trigen, and Uniform.
Most LikelyA range value used for the following distribution types: Constant, BetaPert, Triangular, Trigen, and Uniform.
Remaining DurationThe total duration minus the amount of time already completed.
Risk AssignmentsA summary of all risks and/or scenarios assigned by ID.
Sampling BehaviorDuration ranging only. The behavior for sampling of in-progress activities. For definitions and examples, see Sampling of In-Progress Durations above.
Sampling ValuesA summary for displaying the distribution type plus any range inputs together in the same field.
Start DateThe date the activity begins. If actualized, the date is appended with an asterisk ( * ).
Std.Dev.A range value used for the following distribution types: Normal and Log-Normal.
ThresholdFloating only. The ratio of an activity’s float in the iteration when it comes up for sampling to the activity’s deterministic float (used for pacing only).
Total CostThe total cost of the activity, as calculated by resource assignments.
Total FloatThe float + drift.
TypeThe type of object, e.g. activity, milestone, hammock, etc.
UnitA toggle for ranging in days or % variance.
WBS SequenceA value for sorting when organized by WBS.
Jump to:

Still Need Help?

Click the icon above or visit our support desk.