Understanding the WCAG EM 2.0

The WCAG-EM 2.0 (Website / Digital Product Accessibility Conformance Evaluation Methodology) is WAI's official procedure for the systematic and comparable evaluation of the accessibility of digital products, including websites, apps, and other digital products, according to the Web Content Accessibility Guidelines (WCAG). The EM is a structure for how an evaluation should be performed; it is not an evaluation methodology in itself. Unlike WCAG, it is informative, giving it a different status than the normative WCAG.

Step 1: Define the Evaluation Scope

In the first step of WCAG-EM 2.0, the evaluation scope of the digital product is defined. The goal is to clearly determine which areas of the digital product are evaluated and under what framework conditions the evaluation takes place.

1.1 Define the Scope of the Digital Product

First, the area of the digital product to be evaluated is precisely delimited. This includes defining relevant subdomains, paths, apps, or system boundaries. This clearly determines which components of the digital product are subject to the accessibility evaluation.

1.2 Define the Conformance Target

Next, the conformance target is defined. This includes selecting the underlying WCAG version, for example WCAG 2.1 or WCAG 2.2, as well as defining the targeted conformance level: Level A, AA, or AAA. The chosen conformance level determines which requirements the digital product will be evaluated against.

1.3 Define the Accessibility Support Baseline

In addition, an accessibility support baseline is defined. This specifies which combinations of web browsers, operating systems, and assistive technologies will be considered during the evaluation. Assistive technologies may include screen readers, for example. The baseline thus creates a binding foundation for the technical environments in which the accessibility of the digital product is evaluated.

1.4 Define Additional Evaluation Requirements

Optionally, additional requirements can be defined as part of the evaluation scope. This may include complementary user testing with people with disabilities. Such additional investigations can usefully supplement the technical evaluation according to WCAG and provide further insights into the actual usability of the digital product.

Step 2: Explore the Target Website

In the second step of WCAG-EM 2.0, the digital product is systematically explored. The goal is to gain a comprehensive overview of the different web pages, functionality, content types, and technologies used. This inventory forms the basis for selecting a representative sample later on.

2.1 Identify Common Web Pages

First, the typical content and layout types present in the digital product are identified. These may include homepages, article pages, contact pages, or dashboards. The key is to capture the different web pages and recurring page types so that they are appropriately considered in the subsequent evaluation.

2.2 Identify Essential Functionality

Next, the essential functionality of the digital product is recorded. The focus here is particularly on the core tasks and interaction points of users. Examples include login, search functionality, a shopping cart followed by checkout, or entering and submitting forms.

2.3 Identify the Variety of Web Page States and Types

Furthermore, the variety of included content elements is considered. Different sample types should be captured, such as tables, dynamic widgets, audio and video content, or PDF documents. This ensures that not only simple pages, but also varied and potentially complex content types are included in the evaluation.

2.4 Identify Technologies Relied Upon

Another component of exploring the product is identifying the technologies relied upon by the digital product. These may include HTML, CSS, WAI-ARIA, SVG, JavaScript, and PDF. Knowledge of the technologies used helps to specifically account for the relevant accessibility requirements.

2.5 Identify Other Relevant Web Pages

In addition, other relevant web pages and content that may be significant for the accessibility evaluation are identified. These include an accessibility statement, help pages, or legal notices. Such special pages should also be taken into account when assembling the sample later.

Step 3: Select a Representative Sample

Based on the findings gained in Step 2, a representative sample is assembled in the third step for the actual evaluation. The sample aims to reflect the digital product as comprehensively as possible while enabling an efficient and traceable audit.

3.1 Include Structured Sample

First, a structured sample is compiled. Web pages are specifically selected to cover the previously identified page types, functionality, components, content elements, and technologies. This ensures that the essential characteristics of the digital product are represented in the evaluation.

3.2 Include Random Sample

In addition, a randomly selected sample is added. This comprises roughly 10% of the structured sample and serves to investigate areas that might otherwise be overlooked in an exclusively structured selection. Random selection can help uncover unexpected or previously unidentified accessibility barriers.

3.3 Include Complete Processes

Special attention is given to complete processes. Interaction chains such as registration, a login sequence, or a purchasing process should be included in their entirety from start to finish within the sample. This ensures that accessibility is evaluated not just for individual web pages, but across the entire user task.

Step 4: Evaluate the Selected Sample

In the fourth step, the previously defined representative sample is systematically audited for accessibility. The evaluation is conducted against the WCAG success criteria for the established conformance target. In addition to the core requirements, alternative conformant versions, assistive technology support, and potential non-interfering or blocking content are taken into account.

4.1 Audit All Structured and Random Web Pages

All selected sample items are audited against all relevant WCAG success criteria for the target conformance level. First, it is determined whether the respective content and functionality satisfy the requirements. In addition, it is checked whether conforming alternate versions exist and whether they satisfy the accessibility requirements.

Another crucial element is evaluating accessibility support. It is investigated whether content and functionality are actually usable with the specified combinations of browsers, operating systems, and assistive technologies. Furthermore, non-interference is considered. This includes checking whether content poses physical risks or whether functionality creates a keyboard trap from which users cannot escape on their own.

4.2 Audit Complete Processes

All previously identified complete processes are tested end-to-end. This checks whether a process can be completed from start to finish without barriers. For multi-step tasks, it is not sufficient to evaluate individual steps in isolation; rather, it must be ensured that a registration, form flow, or purchasing process is accessible in its entirety.

4.3 Compare Structured and Random Samples

Next, the results of the structured sample are compared with the results of the random sample. This comparison helps determine whether the structured sample adequately represents the digital product. If additional or previously unidentified barriers are uncovered in the random sample, this may indicate that an expanded sample or further investigation is required.

Step 5: Record the Evaluation Findings

In the fifth and final step, the evaluation results are systematically documented and reported. The objective is to present the evaluation in a transparent, reproducible manner and to clearly map any identified barriers to their corresponding WCAG requirements.

5.1 Document the Outcomes of Each Step

First, the outcomes of all preceding steps are documented. This includes, in particular, the defined evaluation scope, the selected sample, and the test environments used. Furthermore, specifically identified barriers are mapped to the relevant WCAG success criteria. This provides a clear baseline for evaluating and subsequently remediating accessibility issues.

5.2 Record the Evaluation Details

Optionally, further details regarding the execution of the evaluation can be documented. This may include the testing tools used, information about the evaluators involved, and specific test scenarios. Providing detailed documentation enhances the transparency and repeatability of the audit.

5.3 Provide an Evaluation Statement

Optionally, a formal evaluation statement regarding conformance can be generated. This summarizes the extent to which the digital product satisfies the defined requirements. Depending on the results, a distinction can be made between conforming, partially conforming, or non-conforming.

5.4 Provide an Aggregated Score

Optionally, an aggregated score can also be provided. A numerical score or percentage is calculated to provide a high-level summary of the overall accessibility level. While such a value offers general orientation, it does not replace detailed documentation of individual WCAG success criteria and specific accessibility barriers.

5.5 Provide Machine-Readable Reports

Finally, there is the option to provide the evaluation results in a machine-readable format. This enables automated processing, analysis, or integration into other systems. Suitable formats include EARL or JSON-LD.