Risk-Activity Impacts



Words on this page that have been underlined and italicized can be found in the glossary on the right-hand side of the page.

Tip

When a risk occurs, an activity's duration is extended by the specified impact. If, on the other hand, the risk really requires a new activity which then delays the successor, this situation can be better modeled via Existence Risks.

Inherited Assignments

In NetRisk, quantitative probability and impact may be entered at the risk/scenario-level in the risk register.

  • This saves time, as the probability and impact are inherited automatically and do not need to be entered one-by-one

  • Subsequent modifications to the probability or impact are automatically carried down to each assignment

An inherited assignment is identified by an icon next to each value that has been inherited.

  1. Click the Risk  driver.

  2. Click the View button above the top list and choose Risk Register.

  3. Select the desired risk or scenario in the upper list.

  4. Enter a value in the Probability (Quantitative) column.

  5. In the Distribution Type column, click to choose a desired distribution type.

  6. Enter a value in each of the required columns.

    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 orange (for a risk/scenario with no inherited assignments) or red (for a risk/scenario with inherited assignments).

  7. In the lower list, check the box in the Assign column next to the desired activity(s).

Tip

To force all activity assignments to the top, click the Sort icon, uncheck Organize by WBS,,click Assign twice until the down arrow shows up next to it (descending order), and then make sure the list is then scrolled all the way to the top.

Un-inheriting Risks/Scenarios

If an inherited risk assignment has any value modified at the activity level, any modifications to the probability or impact in the register will no longer be carried down to each assignment.


Individual vs. Grouped Assignments

By default, all assignments underneath a given risk with the same probability of occurrence will be impacted in the same iterations as each other as a group. To impact activities individually, uncheck the box in the Correlate Probability column in the lower list. If the column isn't visible, it must be turned on first (see Customizing Columns). For more on individual vs. group assignments, see the Risks section in The Risk Register.

Removing an Assignment

An assignment can be removed from the selected scenario or from all scenarios underneath the same risk - the choice is made when unchecking the box.

  1. Click the Risk  driver.

  2. Click the View button above the top list and choose Risk Register.

  3. Select the desired risk or scenario in the upper list.

  4. In the lower list, uncheck the box in the Assign column next to the desired activity(s).


Activity View

Whereas the Risk Register view is useful for assigning activities to designated risks, the All Activities view is useful for assigning risks to designated activities.

  1. Click the Risk  driver.

  2. Click the View button above the top list and choose All Activities.

  3. Select the desired activity in the upper list.

  4. In the Assign column, check the box next to the desired risk.


In the activity view, risks cannot be created or modified.

Sampling In Parallel vs. In Series

By default, all risk impacts are sampled in parallel. This can be set individually for each risk impact by clicking the dropdown in the Sampling Order column and choosing between In Series and In Parallel.

OptionDefinition
In ParallelLargest impact taken
In SeriesAll impacts added together

Choosing Distribution Types

Choosing a distribution type should be determined by the level of confidence in the values being chosen. When entering the range, the minimum is interpreted as the optimistic estimate, or best case scenario; the most likely is interpreted to be the most likely estimate; and the maximum is interpreted as the pessimistic, or worst case scenario. 

Distribution TypeWhen to Use...
Constant
  • Use if there is no possible range, but rather only one possible value
Beta-Pert
  • Smoother than a triangular
  • Use if you are fairly confident in your estimate for the most likely but want to control how confident you are in the extremes
  • To use Modified Beta, set lambda to any value other than 4 (default)
  • If you set lambda to 0, the probability of the extremes will be lower than with, for example, a Triangular distribution
Log-Normal
  • Use if you know the duration is the product of several other variables
  • For example, many natural biological events can be modeled logarithmically, as can many variables in economics and finance
Normal
  • Use if the minimum estimate is just as likely to occur as the maximum estimate
  • Not recommended for durations, since an activity will be delayed more often than completed early
  • More typical with risk impacts
Triangular
  • Use if your confidence in the most likely is neither high nor low, as the probability of the extremes will be higher than a Beta-Pert but lower than a Uniform
Trigen
  • Use if what's been entered for the minimum and maximum may actually be too conservative, or if the minimum and maximum may not be the absolute minimum and maximum possible
  • Values below the Low % and above the High % will not be sampled
Uniform
  • Use if your confidence in the range is fairly low, as the probability will be the same for all possible values.
  • Not recommended for durations, since an activity will be delayed more often than completed early

Copy/Paste/Fill Down

Once entered, probability and impact ranges 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.


 Quantitative Risk Columns...
ColumnDescription
Activity AssignmentsA summary of all activities assigned by ID. If no user-defined ID exists, the internal ID is shown.
Distribution TypeA shape for organizing a range of values (e.g. durations, impacts, etc.).
High %A range value used when Trigen is chosen for the distribution type.
LambdaA range value used when BetaPert is chosen for the distribution type.
Low %A range value used when Trigen is chosen for the distribution type.
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.
Probability (Quantitative)

The percentage of iterations that the risk will be sampled as occurring.

When setting the qualitative probability, the value from the Qualitative Thresholds window will be copied over to this field, but only if this field is empty. Subsequent changes to the qualitative probability or updating the value in the Qualitative Thresholds window will have no effect.

Sampling OrderA toggle for sampling risk impact in series or in parallel. When sampling In Series, if there are multiple risks impacting the same activity, all the impacts are added together. When sampling In Parallel, if there are multiple risks impacting the same activity, only the largest impact is taken.
Sampling ValuesA summary for displaying the distribution type plus any range inputs together in the same field.
Std.Dev.A range value used for the following distribution types: Normal and Log-Normal.
UnitA toggle for ranging in Days or % Variance.

For qualitative columns, see The Risk Register.

 Activity Assignment Columns...
ColumnDescription
Assign

A checkbox for assigning the activity to the risk.

This column cannot be removed from the table.

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.

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).

Correlate ProbabilityA toggle for determining whether or not the assignment will be correlated. If checked, the sampling of the occurrence of the risk will be sampled in the same iterations as any other assignment with the same probability value.

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

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.
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.
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.
Probability (Quantitative)The percentage of iterations that the risk will be sampled as occurring.
Remaining DurationThe total duration minus the amount of time already completed.
Risk AssignmentsA summary of all risks and/or scenarios assigned by ID.
Sampling OrderA toggle for sampling risk impact In Series or in parallel. When sampling in series, if there are multiple risks impacting the same activity, all the impacts are added together. When sampling In Parallel, if there are multiple risks impacting the same activity, only the largest impact is taken.
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.
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.
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 Glossary

Distribution Type: a shape for organizing a range of outcomes (e.g. durations, impacts, etc.).

Impact: the degree to which the risk could affect activity durations.

Probability: the percentage of iterations the risk will be sampled as occurring.