Here is some additional information for those that have requested it.
The data is completely self-reported data. All respondents were
given a time line as to when specific events occurred (WTC 1 Hit,
Announcement in WTC 2 about WTC 1, WTC 2 Hit, WTC 2 collapsed, WTC 1
Collapsed). Minimally all respondents had some notion as to when thest
things happened. They were then asked when (to the best of their
ability) to provide the estimated time and floor when they specific
actions on their part occurred).
Arrived at work??
First became aware that something unusual had happened.
Concluded that something serious had happened.
Made the decision to evacuate.
Began to evacuate (physically).
Reached the street access level.
Exited on th street.
The correlation between where they started and the time between began
to evacuate and reached the street is .64.
>>>>>>>I saw the original posting and then watched the exchanges about
how to work
this problem. I'd like to ask a really basic question, more out of
than anything else. The question is where did these data come from? I
the popularly published account of the attack (the name of which I
and find it kind of hard to believe that people could recall very
when they started down and when they hit the 'ground floor' however
define that. I doubt also that there were 'official' records of people
coming down. To the extent that the accounts in the book are accurate,
also think that one's velocity down the stairs depended on when one
down. Velocity would have slowed as volume increased and as rescue
started up. But, mainly, I'm curious of the circumstances of the