Likelihood of Failure (LOF) analysis predicts the probability that each asset could fail based on associated properties, spatial interaction with other GIS layers, and asset data that correlates with observed failures in the local system. For example, if the asset is old and made of a material known to fail around its current age, then that asset should have a high LOF score.


Each Likelihood of Failure is based on one or more factors. A project can contain a library with dozens of LOF's which are combined with customized weighting during the Risk calculation. Typical data used in LOF's include asset attribute data (e.g., install date, pipe material) and various GIS data (e.g., Soil type, etc.).

Create/Edit LOF Analysis

To create a new LOF, right-click on the Likelihood of Failure category in the Analysis tab of the Operation Center window and select New.

Then, give the LOF an ID and Description (separate the ID and Description with a comma). Click OK.

The Likelihood of Failure Wizard will open and guide you through the following steps:


Step 1: ID, Description and Selection

This step lets you choose to apply the LOF analysis on the Full Network, a predefined Facility Selection, or by Zone which is defined in asset's Zone field.

Facility Scope

Full Network: Every asset of this type (e.g., gravity main, lateral, manhole) will receive a score for this LOF.

Facility Selection: Every asset of this type (e.g., gravity main, lateral, manhole) that is within the static selection will receive a score for this LOF.

Zone: Every asset of this type (e.g., gravity main, lateral, manhole) that is assigned to the zone selected will receive a score for this LOF. Please note that "zone" is an attribute field for each element type. If there are no values in this field, there will be no options in the zone drop-down menu.


Step 2: Choose a Category

InfoAsset Planner has multiple built-in options for interacting with asset, analysis, and GIS data to create LOFs.

See Analysis Categories below for details on each option.


Step 3: Set Parameters

In this step, the data is defined to score each asset's Likelihood of Failure. The interface varies for each category of analysis.

Refer to the Analysis Categories section below for more details on setting the parameters for each category.


Step 4: Calculate Value

In Step 4, every asset in the assessment scope (Step 1) is listed by Facility ID and the value on which each asset will be scored for this consequence is displayed. In the following step (Step 5), scoring is defined based on the values displayed in step 4.

Normalize value: Choose a field from the drop-down list to divide the value by. For example, you might select pipe length to generate a resulting “number of incidents per pipe length” value. Note: This option is not available if the "Value" field contains non-numerical results (i.e., material results displayed in the above).


Step 5: Set Score Range

In Step 5, consequence scores will be defined based on values shown in Step 4. Depending on the parameter type selected in Step 3, the values may be text or numerical which require different types of scoring. For example, if pipe material is being evaluated, a text field will be scored, so there cannot be a range of values to score. A score would be assigned to each unique material type.  But with a LOF score on pipe diameter, a numerical value, scoring could be done on individual values or on a range of values.

The following dialog box demonstrates scoring ranges based on install dates where the number of classes as well as breaker values to create custom ranges can be defined.

The following dialog box shows the discrete text values returned from scoring on a text field. In this scores will be assigned to specific values. The number of classes does not apply when using text values.

Equal Interval, Natural Breaks, and Quantile methods can be used for automatically assigning breaks to ranges of numerical values:

Quantile - Assigns the same number of data values to each class.

Equal Interval - Divides the data values into equal-sized classes.

Natural Breaks - Classes are set where there are large differences in the data values.

Normalize score by- Choose a field from the drop-down menu to divide the likelihood by. The intent of this tool is to allow you to apply business risk exposure logic to the likelihood calculation.

For example, by choosing the redundancy field containing a value of 2 for all looped and parallel pipes. The likelihood will be divided by 2 for all looped and parallel pipes. For more information, see Calculate Pipe Redundancy.

The Score Chart and Histogram can be used to study the distribution.

Analysis Categories

Pipe Attribute - Predict the likelihood of failure of each asset based on it's direct attribute data (e.g., install date).

Select a facility attribute field, or choose other to select any other field associated to the asset. Please note that the options shown here will vary depending on what asset type the LOF is scoring.

Soil Type - Assign LOF based on soil type data.

Information about soil composition can be used to estimate the likelihood of failure. This information can come from an attribute field associated with the InfoAsset Planner asset layer or from an external GIS layer.

Data Source:

Facility Table - Specify the field in the attribute table that specifies the dominant soil type.

External Soil Layer - Specify the soil layer from layers in the ArcMap table of contents. This layer must be a polygon layer, and the attribute field which stores the soil information must be a string. 

A Query can optionally be used to filter the background GIS layer. Click Query Builder to create a query expression that will refine tasks selected and asset scoring.

Soil Type Field - If the Facility Table is selected as the Data Source, specify the field in the asset's Facility table that indicates what type of soil in which the asset is buried. If External Soil Layer is selected as the Data Source, specify the field in the layer that indicates soil type.

Failure History Data - Use failure history data as a predictor of future failures.

Local conditions that cause pipes to fail often persist after pipe failures are repaired. Information about past failures or repairs can be used as a predictor of future failures in a pipe segment where the causing failure are not remedied. If customer complaints/incidents are tracked and/or work order history is available, then this data could be used in a Failure History LOF.

Select a failure field (field that indicates pipe failure/break), or choose an external GIS layer.

Facility Table - Select this option if the failure data is embedded in the InfoAsset Planner asset layer.

Failure History Layer -  Select this option if the failure data is in a background GIS layer.

Failure Layer - If "Failure History Layer" is selected, this drop-down list will be used to select the failure layer.

Query - If "Failure History Layer" is selected, the a query builder can be used to filter the GIS data.

Searching Distance - If "Failure History Layer", this defines the spatial searching distance that will be used to associate failure points to assets.

Pipe Failure Field - Use this drop-down list to specify which field contains the failure data. This will be used regardless of which data source is selected.

Critical FacilitiesUse the location of critical facilities (e.g., hospitals) to assign higher LOF to nearby or associated assets.

InfoAsset Planner will assign scores based on the distance from each asset to the nearest critical facility, up to an assigned Max Distance set in this interface. Alternately, each critical facility can be assigned directly to assets using a Facility ID Field.

Facility Name - Optional name to be assigned with the facility layer.

Facility Layer - The background GIS layer to be used in the COF.

Facility ID Field - When a field is selected, InfoAsset Planner will omit the spatial search and simply apply True/False values based on direct assignment of Assets to critical facilities. Each critical facility (e.g. hospital) can be assigned one asset (e.g., pipe) using this field. Set this value to Blank to use the spatial search.

Max Distance - The maximum searching distance applied to the spatial join. If an asset is not within this distance from a critical facility, it will not receive a value.

Query - This can be used to filter out unwanted parts of the GIS data. Use the Query Builder to create a query expression that will refine tasks selected and asset scoring.


Service Request - Imported Service Requests (e.g., odor complaints around a sewer main) can be used as an indicator of an asset's likelihood of failure.

Score assets based on imported or created Service Requests.

Count - Score based on the count of service requests associated with the asset.

Type - Score assets based on the type of service requests associated. (Note: If an asset has multiple service requests associated with it, InfoAsset Planner will only use the highest scoring type. The service requests type to score association is set in step 5.)

Status - Score assets based on the status of service requests associated. (Note: If an asset has multiple service requests associated with it, InfoAsset Planner will only use the highest scoring status. The service request status to score association is set in step 5.)

General Info - Score assets based off of fields in the IMIC_SVServiceRequest table. If this option is selected the "Field" drop-down list must be used. (Note: This layer is the default InfoAsset Planner layer used by the Service Request tab. You can add custom fields to this layer if desired.)

Detail Table - Score assets based off of fields in the detail tables for Service Request types. For more information on detail tables and how to use them please see the Service Request Type Manager Section. If this option is selected, the "Field" drop-down list must be used.

Priority - Assets will be scored based on the highest priority service request associated with the asset. The Priority field should be populated in the Service Requests to utilize this option.

A Query can optionally be used to filter the background GIS layer. Click Query Builder to create a query expression that will refine the service requests used in the analysis.

Intersection - Assign likelihood of failure to assets that intersect GIS layers like roads or streams.

Pipes will be assigned values based on their spatial intersection with a selected GIS layer. The external layer can be any layer with associated geometry (line, polygon, or point).

Values will be assigned as either True/False or the Target Field of the associated layer if the asset crosses within the buffer distance of the layer.

Intersection Layer - The background GIS layer to be used in the LOF.

Query - This can be used to filter out unwanted parts of the GIS data. Click Query Builder to create a query expression that will refine tasks selected and asset scoring.

Buffering Distance - The distance that will be used to define an "intersection". In the above example, any asset that came within 200' of a street could count as an intersection.

Target Field -  Use this drop-down list to specify an attribute field in the GIS layer to use for scoring. If this is left blank, the scoring options will be True/False. In the example above, the scoring options would be based off the speed of the road which the asset intersects.


Inspection - Estimate the LOF based on any imported inspection data.

The fields below specify how scores will be determined from associated inspections for each asset. See below for explanations of each option.

Count - Score assets based on of the total number of all associated inspections.

Type - Score assets based on of the type of inspection associated. (Note: If an asset has multiple inspections associated with it, InfoAsset Planner will only use the highest scoring type. The inspection type to score association is set in step 5.)

Status - Score assets based on of the status of inspection associated. (Note: If an asset has multiple inspections associated with it, InfoAsset Planner will only use the highest scoring status. The inspection status to score association is set in step 5.)

General Info - Score assets based on of fields in the IMIC_IPInspection table. If this option is selected the Field drop-down list must be used. (Note: This layer is the default InfoAsset Planner layer used by the Work Manager Inspection tab. You can add custom fields to this layer if desired.)

Detail Info - Score assets based on of fields in the detail tables for Inspection types. For more information on detail tables and how to use them please see the Inspection Type Manager Section. If this option is selected, then the Field drop-down list must be used.

Click Query Builder to create a query expression that will refine tasks selected and asset scoring.

Work Order - Assign likelihood of failure based on associated work orders imported for each asset.

Select a work order parameter and filter to calculate consequence of failure.


Count - Score assets based off of the count of all work orders associated.

Type - Score assets based off of the type of work orders associated. (Note: If an asset has multiple work orders associated with it, InfoAsset Planner will only use the highest scoring type. The work order type to score association is set in step 5.)

Status - Score assets based off of the status of work orders associated. (Note: If an asset has multiple work orders associated with it, InfoAsset Planner will only use the highest scoring status. The work order status to score association is set in step 5.)

General Table - Score assets based off of fields in the IMIC_WOWorkOrder table. If this option is selected the Field drop-down list must be used. (Note: This layer is the default InfoAsset Planner layer used by the Work Manager Work Order tab. The user can add custom fields to this layer if desired.)

Detail Table - Score assets based off of fields in the detail tables for Work Order types. For more information on detail tables and how to use them please see the Work Order Type Manager Section. If this option is selected the Field drop-down list must be used.

A Query can optionally be used to filter the background GIS layer. Click Query Builder to create a query expression that will refine tasks selected and asset scoring.


Pipe Inventory - This is a catch-all category to use any tabular data that can be joined to the assets by a facility ID. This can include tables both inside and outside of the Project Database.

Using Inventory data to calculate consequences is perhaps one of the most flexible methods of calculation.  It can use any number of attributes or data populated manually by the user or data exported from other software packages. In the example below, CCTV defects are being used in the LOF:

Name - Use this to enter a descriptive name for the data being used.

Internal Table - When this option is selected, any default InfoAsset Planner table can be used for scoring the LOF. Click the ellipsis to browse the available tables.

External Table - When this option is selected, any external table or layer can be used for scoring the LOF. Please note that there needs be a field that links each table entry to an asset ID for a background layer to be used.

Query - This can be used to filter the data source so that only the needed entries are scored. Click Query Builder to create a query expression that will refine tasks selected and asset scoring.

Facility ID Field - This drop-down list is used to link the table/layer entries to InfoAsset Planner assets.

Target Field - This drop-down list is used to select the values to be scored.


Reliability - Use the outputs from Deterioration Models to score pipes.

This tool can reference the results from any Deterioration Model, including both Cohort and Regression analyses. This is a powerful combination because Reliability analysis takes out the guess-work of assigning LOF scores by manual grading classes.

Be aware that using reliability analysis as part of a combination of LOF's can result in overlapping scores of attributes. For example, pipe material is a common LOF category, but it is also often included in any reliability analysis. Including both in the final Risk analysis could double the contribution of material as a factor relative to other factors being considered.

Reliability: This drop-down lists any available Reliability analysis results stored in the project.

Query: This can be used to filter the data source so that only the needed entries are scored. Click Query Builder to create a query expression that will refine tasks selected and asset scoring.

Target Field: This drop-down list is used to select one of the available reliability analysis outputs to be used for creating scores.

Multi-Parameter - In some cases, the combination of attributes can behave uniquely from sum of the individual attribute scores. This category can assign individual scores for combinations of existing LOF's.

The Multi-Parameter is configured to score assets based on the combination of multiple existing LOF analyses. Run any supporting LOF analyses first, then create a Multi-Parameter LOF which combines them with unique scoring.

In the first step, simply select two or more existing LOF analyses that will be used to calculate the final likelihood of failure score.

The example below shows the scoring configuration which emphasizes the combination of install date with certain material types. When the material LOF score is between 4-7 (referencing certain materials displayed in the bottom table for assistance), and the Date Install score is between 4-5, the effective score for pipes with that score criteria is 10. 

Note that in the bottom reference table, cells are highlighted based on the selected row in the top table. This is to help confirm the values included in each row of scoring ranges.


Managing LOF Library

Like many other features of InfoAsset Planner, objects in the expandable tree can be managed by right-clicking to access a pop-up menu.

The following menu appears when any individual Likelihood of Failure in the Operation Center is right clicked:

Description - Add or edit description.

Delete - Deletes the consequence object Run - Run the calculation again Reports - Open the consequence scoring ranges used or the report with calculated scores.

Clone - Copy the selected LOF to be pasted in creating a new LOF.

Run - Re-run or just edit the existing LOF.

Reports - Access the reports that have been generated from the previous run of the selected LOF.

Map Display - Create a customized map theme for the selected analysis results.



*Note: Be sure to re-run the LOF analysis any time that the underlying input data changes to reflect the latest results.