5 Step Human Factors Product & Process Quick Guide for Ensuring:
Usability, Efficacy, Efficiency, Accessibility, Safety, & Delight


Five Step Human Factors Process:

Step 1 - Define, document, & obtain product team review & approval of the customized Human Factors Plan – the schedule of the Human Factors product deliverables, product deliverable dependencies, high level product timelines, & essential product team collaboration resources.

Step 2 - Understand, define, & document the product WHO, WHAT, WHERE & WHEN, WHY, & HOW:  intended use, intended users, intended use audiences, intended user tasks, intended use environments, intended use equipment/materials, intended support/reference resources, & any possible or probable user/use limitations &/or disabilities.

Step 3 - Create a formative evaluation plan for concept designs (Option A vs. Option B) utilizing workflow assumptions (e.g. low-fidelity prototype usability evaluations, card sorting exercises, cognitive walkthroughs, &/or competitive analyses). 

Conduct formative design valuation session(s) with representative users face-to-face, or remote including follow-up user surveys to measure perceived efficacy, error handling, efficiency, & delight (Net Promoter Score - How likely are you to recommend the product to a colleague? 0 - not likely to 10 - very likely: Why - please explain your rating score?)

Step 4 - Iterate product prototype designs based on formative usability evaluation observation results, user interactions with prototype(s), use error(s) observed, & user feedback in preparation for summative evaluation. 

Create a summative evaluation plan & create summative prototype(s). 

Conduct summative usability evaluation(s) utilizing high-fidelity prototypes (Option A vs. Option B) with representative users. Evaluate user feedback based on efficacy, error handing, efficiency, & delight (Net Promoter Score - How likely are you to recommend the product to a colleague? 0 - not likely to 10 - very likely: Why - please explain your rating score?)

Generate summative testing results findings report with final design recommendations. Update final product designs (user interface, training materials, packaging, & user flows), based on summative usability result findings. 

Step 5 - Generate a Human Factors Report documenting the comprehensive project research findings & usage summary pertaining to product safety, efficiency, efficacy, & delight.

Project Deliverables & Activities by Step (WHO, WHAT, WHERE & WHEN, WHY, & HOW)

Step 1 - HUMAN FACTORS PLAN –
the WHAT activities & HOW deliverables required throughout the project process WHEN

Step 2 - USER ANALYSIS –
the attributes of the WHO will use the product, as well as WHO will be the recipient of the products usage. Identifies & defines the primary, secondary, & tertiary user groups (gender, age, attributes specific to product use). HOW, WHEN will each user group interact with the product, as well as whether or not there will be both a product actor(s) as well as recipient(s) of the product actions (e.g patients).

Step 2 - USE ENVIRONMENT ANALYSIS –
the WHERE the product will be used WHAT

Step 2 - USE ERROR ANALYSIS –
the WHAT doesn’t work, WHY errors occurred, & criticality of the errors - by WHOM

Step 2 - TASK ANALYSIS –
the WHAT the user WHO needs to perform each task, in WHAT order, WHERE & WHEN

Step 2 - INTENDED USE –
the WHAT the product is intended to be used for, by WHOM, WHERE, WHY, HOW, & WHEN

Step 3 - FORMATIVE TEST PLANS –
the WHAT, WHERE, WHY, & HOW plans for the initial usability testing with representative users WHO

Step 3 - FORMATIVE PROTOTYPE –
the WHAT functionality supporting user tasks (lower fidelity) WHO

Step 3 – FORMATIVE TEST RESULTS –
the WHAT results from all formal testing of representative users WHO, & recommendations for response to all findings WHAT, WHERE & WHEN, WHY & HOW

Step 4 - SUMMATIVE TEST PLANS –
the WHAT, WHERE, WHY, & HOW plans for final validation testing with representative users WHO

Step 4 - SUMMATIVE PROTOTYPE –
the WHAT functionality supporting user tasks (higher fidelity) WHO

Step 4 - SUMMATIVE TEST RESULTS –
the WHAT results from all final testing of representative users WHO, & recommendations for response to all findings WHAT, WHERE & WHEN, WHY, & HOW


Step 5 - HUMAN FACTORS REPORT –
the summary of WHO, WHAT, WHERE & WHEN, WHY, & HOW the plan was followed at each development stage, each plan stage findings, & details regarding the design & development findings reactions taken, final determination of product safety, efficiency, efficacy, & delight.

Step 5 - USER INTERFACE DESIGN DOCUMENT –
the WHAT, WHY & WHERE requirements for the software user interface design, user workflow WHO, screen flow WHEN, & user interactions HOW.

IEC 62366 -

International standard that covers the application of usability engineering to medical devices. Helps medical device manufacturers consider human factors by offering a standardized process for analyzing the usability of medical devices. Ensures that the User Interface (UI) of a medical device has been rigorously evaluated for user & patient safety. IEC 62366 is broken into 2 parts:

  1. IEC 26366-1 - Application of usability engineering to medical devices. Also labeled as IEC 62366:2015 + A1:2020

  2. IEC 62366-2 - Guidance on the application of usability to engineering to medical devices. Technical report which contains background information & guidance on implementing IEC 62366-1 & does NOT specify any requirements. Also labeled as IEC 62366-2:2016

Steps to ensure that the User Interface (UI) of a medical device has been rigorously evaluated for user & patient safety:

  • Define intended users, use environments, & user interface.

  • Identify use-related hazards.

  • Identify & categorize critical tasks.

  • Develop & implement risk mitigation/control measures.

  • Validate user safety & effectiveness.

  • If validation shows that use-related risks are unacceptable, or that new use-risks have been introduced, you must return to the previous step & implement effective risk control measures.

  • Document Usability Engineering (UE)/Human Factors (HF) process.

It is important to note that usability engineering validation of devices takes two forms, formative evaluations & summative evaluations.

Formative Evaluations: conducted while a device is still in design & development. These evaluations are used to address safety concerns that emerge during preliminary analyses or to explore different design options for the UI before it’s finalized. You may end up carrying out multiple formative evaluations.

Summative Evaluations: conducted during the design validation stage of a device. A summative evaluation is much more rigorous than a formative evaluation, as it goal is to demonstrate the the UI is safe for users. Testing should involve the intended end users of the device engaging with the final UI design under realistic conditions in realistic environments.

Intent of IEC 62366

The usability engineering goal is to identify & mitigate any use-related hazards & risks, & to create a UI that encourages error-free use of the device. The user may be a doctor or other healthcare provider, but in some cases the device may also be operated by a patient with no clinical background.

Usability Engineering & Human Factors requires the analysis of the interaction between the intended user & and the device, including:

  • The information users perceive from the device, as well as its labeling, packaging & instructions.

  • How users interpret that information to make decisions regarding the operation of the device.

  • How they use the device - manipulating its components, controls, settings, etc.

It’s also essential to consider the opposite transfer of information from the user to the device.

  • How does the device receive inputs from the user?

  • How does the device respond to the user & provide feedback about the effects of their decision to manipulated the device in a specific manner?

When usability engineering & human factors is done properly, it has a host of benefits for both users, patients, & medical device companies. Devices become easier to user, which results in the reduced risk of user error, adverse events, & product recalls.