PowerMapper
PowerMapper
Techniques for WCAG 2.0 and 2.1 Screen reader compatibility
Shows how WCAG sufficient techniques and failures behave in commonly used screen readers.
The results include two types of test:
- Expected to work - these tests show support when accessibility features are used correctly
- Expected to fail - these tests show what happens when accessibility features are used incorrectly
WCAG sufficient techniques - reliability by user agent
Reliability of WCAG sufficient techniques in different screen reader / browser combinations. Expected failures (e.g. missing ALT on an IMG) are not included in the reliability graph.
The solid area in the graph shows percentage of tests that pass in all tested interaction modes. The cross hatched area shows partial passes that only work in some interaction modes.
An example of a partial pass is when form labels are read when tabbing, but ignored in browse mode.
| Combo | Versions | Reliability | Test Changes |
|---|---|---|---|
| JAWS Chrome | JAWS 2025.2508.120 with Chrome 143 | 3 better | |
| JAWS Edge | JAWS 2025.2508.120 with Edge 143 | 1 better | |
| JAWS Firefox | JAWS 2025.2508.120 with FF 140 | 23 better | |
| JAWS IE | JAWS 2019.1912.1 with IE11 | 21 better | |
| NVDA Chrome | NVDA 2025.3 with Chrome 143 | 7 better | |
| NVDA Edge | NVDA 2025.3 with Edge 143 | 5 better | |
| NVDA Firefox | NVDA 2025.3 with FF 140 | 27 better | |
| NVDA IE | NVDA 2019.2 with IE11 | 4 better | |
| VoiceOver Mac | VoiceOver macOS 15.7 with Safari 26.0 | 22 better | |
| VoiceOver iOS | VoiceOver iOS 18.6 with Safari iOS 18.6 | 11 better | |
| WindowEyes IE | WindowEyes 9.2 with IE11 | 14 better 1 worse | |
| Dolphin IE | Dolphin SR 15.05 with IE11 | ||
| SaToGo IE | SaToGo 3.4.96.0 with IE11 | ||
| Average | Including older versions |
The average includes all versions, but some browser/AT combinations have tests for multiple versions (NVDA / JAWS / VoiceOver), while others only have tests for a single version (SaToGo and Dolphin).
WCAG sufficient techniques - reliability trend
This graph shows reliability over time for WCAG techniques in NVDA, JAWS and Voiceover. Other screen readers don't have enough historical data yet to plot trends.
WCAG sufficient techniques - very reliable
These are WCAG sufficient techniques, and work reliably across all tested screen readers, including older versions.
These work in 100% of the tested screen reader / browser combinations.
| Screen Reader | NVDA | JAWS | VoiceOver | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Browser | Edge | FF | Cr | Edge | FF | Cr | Mac | iOS | |
| Reliability when used correctly (100% average) | 100% | 100% | 100% | 100% | 100% | 100% | 100% | 100% | |
ARIA16 input type=text with aria-labelledby attribute | |||||||||
H30 Link containing img with alt | |||||||||
H36 input type=image with alt | |||||||||
H37 img with alt | |||||||||
H44 input type=text with label for | |||||||||
H67 img with null alt | |||||||||
WCAG 3.1.1 Page with lang set on the html and p elements | |||||||||
WCAG 3.1.1 text/html page with mismatching lang and xml:lang on the html element | |||||||||
WCAG sufficient techniques - reliable in recent versions
These are WCAG sufficient techniques which are expected to work, and work in the latest versions of screen readers, but not in older versions.
- Works reliably in all versions of this combination of screen reader and browser
- Works reliably in the latest version of this combination of screen reader and browser (improved support)
100% of these techniques are not accessibility supported (i.e. cause failures) in one or more of the tested screen reader / browser combinations. On average they cause failures in 10% of the tested combinations.
WCAG sufficient techniques - not fully reliable
These are WCAG sufficient techniques, and are expected to work, but don't work in the latest versions of some screen readers.
- Works reliably in all versions of this combination of screen reader and browser
- Works reliably in the latest version of this combination of screen reader and browser (improved support)
- Don't work in the latest version of this combination of screen reader and browser, but used to work in older versions (regression)
- Don't work in any version of this combination of screen reader and browser
100% of these techniques are not accessibility supported (i.e. cause failures) in one or more of the tested screen reader / browser combinations. On average they cause failures in 46% of the tested combinations.
WCAG failures
These are WCAG failures, and are expected to fail.
100% of these techniques fail in one or more of the tested screen reader / browser combinations. On average they cause failures in 74% of the tested combinations.
Key
- Stable - works, or doesn't cause problems, in all versions of a specific combination of screen reader and browser
- Better - works, or doesn't cause problems, in the most recent version of a specific combination of screen reader and browser (improvement)
- Worse - causes problems in the most recent version of a specific combination of screen reader and browser, but used to work in older versions (regression)
- Broken - causes problems in all versions of a specific combination of screen reader and browser
Test notes
All tests were carried out with screen reader factory settings. JAWS in particular has a wide variety of settings controlling exactly what gets spoken.
Screen readers allow users to interact in different modes, and can produce very different results in each mode. The modes used in these tests are:
- Reading Content read using the “read next” command in a screen reader
- Tabbing Content read using the “tab” key in a screen reader
- Heading Content read using the “next heading” key in a screen reader
- Touch Content read when touching an area of screen on a mobile device
In the “What the user hears” column:
- Commas represent short pauses in screen reader voicing
- Full Stops represent places where voicing stops, and the “read next” or “tab” or “next heading” command is pressed again
- Ellipsis … represent a long pause in voicing
- (Brackets) represent voicing that requires a keystroke to hear