Attribute Related Measures: Operational Resiliency


1. Recordable incidents of injury or illnesses

Description: Incidence rates can be used to show the relative level of injuries and ill­nesses and help determine problem areas and progress in preventing work-related injuries and illnesses.

Example calculations:
The U.S. Bureau of Labor Statistics has developed instructions for employers to eval­uate their firm’s injury and illness record. The calculation below is based on these instructions, which can be accessed at: http://www.bls.gov/iif/osheval.htm.

  • Total recordable incident rate: (Number of work-related injuries and illnesses X 200,000[1]) ÷ employee hours worked.

2. Insurance claims

Description: This measure examines the number, type, and severity of insurance claims to understand insurance coverage strength/vulnerability.

Example calculations:

  • Number of insurance claims: Number of general liability and auto insurance claims per 200,000[2] employee hours worked.
  • Severity of insurance claims: Total dollar amount of general liability and auto insur­ance claims per 200,000[3] employee hours worked.

3. Risk assessment and response preparedness

Description: This measure asks whether utilities have assessed their all-hazards (natu­ral and human-caused) vulnerabilities and risks and made corresponding plans for critical needs. Risk assessment in this context includes a vulnerability assessment regarding, for example, power outages, lack of access to chemicals, curtailed staff availability, etc.

Example calculations:

  • Emergency Response Plan (ERP) coverage and preparedness:
    • Does the utility have an ERP in place (yes/no)?
    • Number and frequency of ERP trainings per year: 100 X (number of employ­ees who participate in ERP trainings ÷ total number of employees).
    • Number and frequency of ERP exercises per year: 100 X (number of employ­ees who participate in ERP exercises ÷ total number of employees).
    • Frequency with which the ERP is reviewed and updated.
  • Vulnerability management: Is there a process in place for identifying and addressing system deficiencies (e.g., deficiency reporting with an immediate remedy process) (yes/no)?

4. Ongoing operational resiliency

Description: This measure assesses a utility’s operational reliability during ongoing/routine operations.

Example calculations:

  • Uptime for critical utility components on an ongoing basis (percent): 100 X (hours of critical component uptime ÷ hours critical components have the physical poten­tial to be operational). Note: a utility can apply this measure on an individual component basis or summed across all identified critical components. Also, a utility can make this measure more precise by adjusting for planned maintenance periods.

5. Operational resiliency under emergency conditions

Description: This measure assesses the operational preparedness and expected respon­siveness in critical areas under emergency conditions.

Example calculations (all apply to emergency conditions and, where relevant, factor in anticipated downtimes relative to required/high demand times):

  • Power resiliency: Period of time (e.g., hours or days) for which backup power is avail­able for critical operations (i.e., those required to meet 100 percent of minimum daily demand). (Note: “minimum daily demand” is the average daily demand for the lowest production month of the year.)
  • Treatment chemical resiliency: Period of time (e.g., hours or days) minimum daily demand can be met with water treated to meet SDWA standards for acute contaminants (i.e., E.coli, fecal coliform, nitrate, nitrite, total nitrate and nitrite, chlorine dioxide, turbidity as referenced in the list of situations requiring a Tier 1 Public Notification under 40 CFR 141.202), without additional treatment chemical deliveries. (Note: “minimum daily demand” is the average daily demand for the lowest production month of the year.)
  • Critical parts and equipment resiliency: Current longest lead time (e.g., hours or days) for repair or replacement of operationally critical parts or equipment (cal­culated by examining repair and replacement lead times for all identified critical parts and equipment and taking the longest single identified time).
  • Critical staff resiliency: Average number of response-capable backup staff for criti­cal operation and maintenance positions (calculated as the sum of all response-capable backup staff ÷ total number of critical operation and maintenance posi­tions).
  • Treatment operations resiliency (percent): Percent of minimum daily demand met with the primary production or treatment plant offline for 24, 48, and 72 hours. (Note: “minimum daily demand” is the average daily demand for the lowest pro­duction month of the year.)
  • Sourcewater resiliency: Period of time (e.g., hours or days) minimum daily demand can be met with the primary raw water source unavailable. (Note: “minimum daily demand” is the average daily demand for the lowest production month of the year.)

More information on resources for this attribute-related measure can be found in the EUM Resource Toolbox.


[1] 200,000 hours is a standard number used by OSHA to normalize data. It represents the equivalent of 100 employees working 40 hours per week, 50 weeks per year, and provides the standard base for the incidence rates.

[2] See the explanation in the footnote above regarding the 200,000 hours standard.
[3] See the explanation in the footnote above regarding the 200,000 hours standard.