9.2The Numbers

Factor	Impact	Data
User base	~15-20% of global population has some form of disability	WHO, 2023
Aging population	Users over 65 benefit from accessibility features	Growing ~3%/year globally
Situational disabilities	Bright sunlight, broken arm, noisy environment, slow connection	Affects all users at some point
SEO benefit	Accessible sites rank higher (semantic HTML, alt text, headings)	Measurable in search rankings
Performance correlation	Accessible sites tend to be faster (clean HTML, no heavy JS overlays)	Core Web Vitals overlap
Brand reputation	Public accessibility failures generate negative press	Multiple case studies

The Disability Market

• 1.3 billion people worldwide have significant disabilities (WHO)
• In the US alone, people with disabilities have $490 billion in disposable income
• 71% of users with disabilities will leave a website that is not accessible (Click-Away Pound Survey)
• When those users leave, they rarely come back -- they go to competitors

The Curb Cut Effect

The "curb cut effect" describes how accessibility improvements benefit everyone, not just people with disabilities:

Accessibility Feature	Primary Beneficiary	Everyone Benefits
Captions on videos	Deaf/hard of hearing users	People in noisy environments, non-native speakers
Keyboard navigation	Motor-impaired users	Power users, developers
High contrast text	Low vision users	Everyone in bright sunlight
Voice control	Users who cannot type	Drivers, people cooking
Simple language	Cognitive disabilities	Non-native speakers, everyone
Alt text on images	Screen reader users	Users with slow connections (text loads first)