To reduce real-world accessibility barriers—beyond simply maintaining clean issue counts—an accessibility specialist needs to take 3C’s things into account. That’s the only combination that can help ensure effective accessibility testing: Coverage, Completeness, and Correctness. Let’s break down why each “C” matters.

Coverage

Think of coverage as the breadth of your testing scope—how many WCAG Success Criteria (SC) your tools can assess.

Unlike modern tools designed for breadth and context, legacy accessibility solutions limit automated accessibility testing for less than half of all WCAG criteria, leaving many potential barriers undetected. This creates a real challenge for teams as they need to manually detect accessibility issues.

Instead, a solution like BrowserStack, powered by the Spectra™ Rule Engine, can provide best-in-class coverage that automates issue detection for 40+ WCAG SCs and finds more issues automatically, which is beneficial.

Completeness

Surface-level checks are insufficient, even for the success criteria tested by a tool. Research shows that most tools detect fewer than 50% of actual accessibility issues due to limited depth and nuance in their WCAG coverage.

Spectra™ addresses this challenge by incorporating specific rules for each success criterion and employing AI-agents that mimic human behavior to identify actual barriers while reducing false positives. This capability helps Spectra™ uncover 66% more critical issues than legacy tools in the market.

Correctness

With BrowserStack we focus the advanced detection by Spectra™ to reliably uncover genuine accessibility barriers while we minimize false positives. While precision reduces distractions, an overemphasis on avoiding false positives can lead to false negatives—meaning actual issues get overlooked. In accessibility, letting genuine barriers slip through unchecked is far more costly than handling a few benign alerts.

Let’s understand this with some numbers: Consider a steep 5% false positive rate with automated accessibility issue detection; it’s important to keep in mind that it still means 95% of unaddressed issues are genuine accessibility barriers that will continue to affect users if unresolved. In this case, precision alone isn't sufficient if you're overlooking significantly more than you're identifying

Why the 3Cs together are greater than the sum of their parts

Accessibility goes beyond meeting WCAG requirements or maintaining issue counts. It involves removing barriers for users. By adhering to the 3Cs—Coverage, Completeness, and Correctness—you ensure your testing is:

  • Inclusive (addresses a wide range of criteria).
  • Meaningful (detects depth and nuance).
  • Actionable (precise enough to trust).

The 3Cs are not just a catchphrase; they are essential for creating accessible, high-impact digital experiences. When selecting an accessibility testing tool, consider the following:

  • Coverage: Choose a tool that covers a broad range of WCAG Success Criteria. Without comprehensive coverage, many barriers remain unnoticed.
  • Completeness: Select a tool that employs AI agents and advanced techniques to identify complex issues. Without this depth, significant problems may go undetected.
  • Correctness: Every accessibility issue flagged is rooted in meaningful accuracy—it is an insight and not noise.
Even the best automated tools can misfire, leading to false positives—flags that aren’t real issues. It's important to remember that some accessibility issues, for example, identifying decorative images require human-like context for validation—and these shouldn't be treated as noise. If these are left unchecked, false positives can give a false sense of compliance and at the same time increase the amount of time a team spends on identifying these issues.

Choosing the right balance

In accessibility testing, neither coverage, completeness, nor correctness should stand alone. Maximizing coverage offers the promise of finding more barriers—but without careful control of false positives, that promise risks becoming noise. Conversely, perfect correctness may mean you miss addressing a real issue, leaving users underserved.

We believe the smart path lies in balance: tools that combine broad coverage with minimal false positives offer the greatest real-world value. Unlike tools that focus narrowly on accuracy or chase inflated detection numbers, our solution gives you both reach and reliability.

Enhance accessibility testing with Spectra™

In today's digital landscape, ensuring that your applications and websites are accessible to all users is not just a best practice but a necessity. With BrowserStack, you’re choosing more than just precision or reach—you’re choosing effectiveness. We deliver the wide accessibility coverage your product needs, while ensuring that the issues we flag are meaningful and actionable. The result? Stronger compliance, better user experiences, and confidence that your accessibility efforts are well-grounded.

Spectra™ and AI agents power the all-in-one accessibility suite of BrowserStack to detect and address accessibility issues effectively. It enables developers and testers to streamline their processes, ensuring compliance with accessibility standards and improving the overall user experience for individuals with disabilities.

With BrowserStack Accessibility Testing, powered by the Spectra™ Rule Engine, you can:

  • Automate detection of true accessibility barriers that would otherwise require manual grunt work for issue detection. BrowserStack strikes the right balance: over 40 WCAG SCs, stronger detection, and minimal false positives.
  • Reduce manual effort, especially on issues already identified as critical or serious.
  • Customize your focus, toggling off “needs review” or “best practices” in settings to hone in on what matters most and easily prioritize—because accessibility cannot be fixed in a day; it’s an ongoing process.

Experience the difference of using BrowserStack’s best-in-class automated issue detection yourself. Sign up for a free trial.