08/04/2010 08:09 pm ET | Updated May 25, 2011

K Plus 5 -- What We Know, and What We Don't

LONDON -- The fifth anniversary of the flooding of New Orleans occurs at the end of this month, and the Times-Picayune takes the occasion to print thank-you notes from some New Orleanians to those who've helped them. Moving and emotional stories are recounted in these notes.

Behind the emotions, of course, are facts. We know now what we didn't know Aug. 29, 2005 -- precisely why the city flooded, why these people were put in such peril. It was not the same thing that happened to people on the Mississippi Gulf Coast, whose homes were hammered that day by the winds of Hurricane Katrina. If this story is new to you, the eminent scientists who led the two independent investigations of the flooding are two of the main personalities in The Big Uneasy, my documentary film about the event and its aftermath. End of plug.

Those facts are known, and knowable. Astonishingly, other facts are not known. Like: how many of the evacuees who were bused, helicoptered, or otherwise transported away from danger during that week in 2005 are happy in their new locales and how many want to come back home? According to the Greater New Orleans Community Data Center's Allison Plyer, we don't know, and we don't have a way of knowing. Not that that would be an important datum in assessing the recovery.

We're left with Barbara Bush's assertion that the folks gathered in the Astrodome were better off, or with my friend who works for the housing department in New Orleans telling me that "my phone rings off the hook every day with people wanting to come home." Anecdotes must suffice, because facts, besides being stubborn things, appear to be expensive things as well.