Use Related Risk Analysis (URRA) – A Critical Living Tool within the Human Factors Process

Use Related Risk Analysis

The leading cause of deficiencies in 542 human factors (HF) submissions reviewed by CDRH in 2019 was use-related risk analysis (URRA) [1]. This is according to a webinar presented by Dr. Hanniebey Wiyor, at FDA CDRH in October 2020. Let’s shed light on common issues identified by FDA CDRH in URRAs and introduce the Kymanox approach to URRA and task categorization.

Use Related Risk Analysis Definition and Common Issues

URRA is the process through which a manufacturer documents potential hazards and harms that end users may encounter via interaction with their product’s user interface. FDA CDRH outlines that Sections 2-7 (Figure 1) of the FDA-recommended HFE/UE Report structure encapsulate a manufacturer’s overall URRA process [2].

Outline of HFE_UE report
Figure 1. Outline of HFE/UE report

An effective URRA is a dynamic process that necessitates revision throughout the product development cycle and during post-market surveillance. Manufacturers should update their URRAs a minimum of four times as the product design evolves and data is collected. Guidance documents and industry standards suggest that Task Analysis, PCA Analysis, Failure Modes and Effects Analysis, and Fault Tree Analysis are acceptable methods. FDA acknowledges the difficulty in estimating the probability of use errors and emphasizes focusing on the potential harm of use errors [2, 4]. The key outcome of a URRA is the categorization of tasks and identification of critical tasks, which become the focus of HF validation testing [2].


Common issues involving URRA during HF reviews by regulators include:

  • No URRA provided
  • Unclear determination of critical tasks
  • Submitting the entire risk management report, forcing the HF reviewer to locate and review use-related risk portions
  • Elimination or selection of critical tasks based on risk priority number (specific to Failure Modes and Effects Analysis)
  • Inappropriate determination of the levels of severity of harm
  • Non-specificity of risk mitigation control information [1]

These issues illustrate a common disconnect between the URRA process and HF activities. A clear connection between URRA and HF is necessary for manufacturers to achieve the end goal, which is to “Maximize the likelihood that new medical devices will be safe and effective for the intended users, uses, and use environments” [2].

Kymanox Approach to URRA Development and Critical Task Identification

Kymanox employs the human factors engineering process shown in Figure 2 when supporting the development of medical devices and combination products. The URRA development process resides within Phase 1, Concept & Design, and Phase 2, Testing, Re-design & Instructional Labeling. New information from preliminary HF activities can trigger iterations of the URRA during Phases 1 and 2. In Phase 3, Clearance and Marketing, the URRA identifies all critical tasks for HF validation testing, feeds into the residual risk evaluation, and potentially a risk-benefit analysis (RBA). It’s worth noting that unanticipated use errors during HF validation testing may necessitate further revisions of a URRA and subsequent HF testing.

During Phases 1 and 2, the manufacturer should document all tasks, use-related hazards, foreseeable use errors, potential harms, and the severity of potential harms. Additionally, the URRA should identify specific risk control measures meant to eliminate or mitigate the occurrence of foreseeable use errors. Before entering Phase 3, a manufacturer should have high confidence that they have identified and can test all critical tasks during HF validation testing.

Case Study – Iteration of a Use Related Risk Analysis

To illustrate a URRA iteration during Phases 1 and 2, let’s use an example formative evaluation with a single-dose auto-injector. Most single-dose auto-injectors have a similar operational sequence, including removing a cap, activating the device to inject a dose of medication, waiting for the full dose to be administered, and then removing the auto-injector. See Table 1 for one example row of a URRA for the formative evaluation.

URRA for a Formative

The blue highlighted data in Table 2 show that risk control measures documented in Table 1 were not effective in mitigating the use error of twisting the cap. Risk control measures added and highlighted in yellow in Table 3 demonstrate how a URRA could be iterated based on formative evaluation data. Additionally, the risk control measures added in Table 3 are inherent safety by design, which is a best practice and most likely to be effective in mitigating use-related risk [5].

Critical Task Identification

Identifying critical tasks can be challenging. However, for medical devices to be reviewed by FDA CDRH, insight has been provided regarding their expectation when labeling a task as critical. A critical task is defined as, “A task which, if performed incorrectly or not performed at all, would or could cause serious harm to the patient or user, where harm is defined to include compromised medical care,” [2].

In our experience, the words “serious” and “compromised medical care” trigger debates when going to define critical and non-critical tasks. However, FDA CDRH pointed to 21 CFR 803.3 (w) shown in Figure 3 to provide insight on this matter [1]. When you compare 21 CFR 803.3 (w) to the five-level qualitative severity levels in ISO 14971 shown in Figure 4; tasks with foreseeable use errors and associated potential harms that are serious, critical, or catastrophic would be labeled as critical.

Figure 3. Content of 21 CFR 803.3 (w).
Figure 4. Example of five-level qualitative severity rankings.

Summary: Use Related Risk Analysis in the Human Factors Process

This article clarifies critical task definitions and emphasizes treating URRA as a process. With extensive experience, the Kymanox team consults on URRAs, seamlessly integrating HF data into a manufacturer’s risk management. Reach out to connect on your next project. We stand ready to support URRA creation, critical task definition, and HF data collection for safe and effective end-user task completion.


[1] Wiyor, H.D. (October 22, 2020). Risk Assessment of Medical Products in Human Factors Submissions with a Focus on EU countries. MHFN Webinar.

[2] FDA guidance entitled, Applying Human Factors and Usability Engineering to Medical Devices that was published by CDRH, FDA on February 3, 2016.

[3] AAMI TIR59:2017 – Integrating Human Factors into Design Controls.

[4] FDA draft guidance entitled, Contents of a Submission for Threshold Analyses and Human Factors Submissions to Drug and Biologic Applications that was released September 2018.

[5] ANSI/AAMI/ISO 14971:2019, Medical Devices – Application of risk management to medical devices.

[6] FDA draft guidance entitled, Human Factors Studies and Related Clinical Study Considerations in Combination Product Design and Development that was published in February 2016.

[7] Office of Surveillance and Epidemiology (OSE) – Divisions. Content last updated March 23, 2020. Retrieved from