To err is human
• accident reports ..
– aircrash, industrial accident, hospital mistake
– enquiry … blames … ‘human error’
• but …
– concrete lintel breaks because too much weight
– blame ‘lintel error’ ?
… no – design error
we know how concrete behaves under stress
• human ‘error’ is normal
– we know how users behave under stress
– so design for it!
• treat the user at least as well as physical materials!