Middle-Aged Users’ Declining Web Performance Jakob Nielsen’s alert

• Between the ages of 25 and 60, people’s ability to use websites declines by 0.8% per year — mostly because they spend more time per page, but also because of navigation difficulties.

Mainstream Aging vs. Senior Citizens

• A typical senior at 75 is 40 years older than a typical mainstream user at 35, so 0.8% per year should correspond to only a 32% slow-down for seniors however for people aged over 60 aging accelerates drastically, and especially after 70 years.
• Curves of cognitive, perceptual, and motor-skill decline have a hockey-stick shape.
• So, the 0.8%/year slow-down is valid only for the mainstream period of 25–60 years of age. For older users, performance declines faster. After 65 years of age or so, differences in user needs are so drastic that we require explicit steps to cater to them.
• This is why there are separate usability guidelines for making websites usable for seniors.

Two actions suggested:

• When doing user testing, make sure to include test participants across the entire age range you’re targeting.
• Don’t believe everything your 25-year old Web designers tell you about “what’s easy” — especially if your target audience is 50-year-old corporate managers.