Wednesday, August 15, 2007

"Absence of evidence is not evidence of absence"

Too often, lack of conclusive evidence about a product, practice, or principle is prematurely interpreted as proof of lack of value or validity. This pattern of fallacious reasoning can be applied equally inappropriately by opponents of long-standing practices in education (such as lectures) or by opponents of new practices which are perceived as threatening (use of cell phones).
The quotation, excerpts, and article referenced below provide a better explanation of this fallacy and how to avoid it.

"Absence of evidence is not evidence of absence."Carl Sagan,US astronomer & popularizer of astronomy (1934 - 1996) - found on "The Quotations Page" 2007-08-15 at

"dangers of misinterpretation of non-significant results"

"…we must question whether the absence of evidence is a valid enough justification for inaction."

"…we should first ask whether absence of evidence means simply that there is no information at all."

"While it is usually reasonable not to accept a new treatment unless there is positive evidence in its favour, when issues of public health are concerned we must question whether the absence of evidence is a valid enough justification for inaction. ... Can we be comfortable that the absence of clear evidence in such cases means that there is no risk or only a negligible one?"

Above 4 excerpts from:

"Statistics notes: Absence of evidence is not evidence of absence" [Link works as of 2007-08-15]
Douglas G Altman, J Martin Bland, BMJ (British Medical Journal) 1995; 311:485 (19 August). "BMJ is published by BMJ Publishing Group Ltd, a wholly owned subsidiary of the British Medical Association"

Volunteer Work New Orleans MERLOT Conf Aug 6 2007

The annual MERLOT conference last week in New Orleans was even more useful and enjoyable than previous ones. Thanks to Diane Didier from the Louisiana Board of Regents. With the support of the MERLOT Conference Program Committee, she organized a volunteer work day on August 6.

So Sally [Gilbert] and I had the privilege of joining about 30 others last Monday for a half-day of "recovery" painting on the third floor of the John Dibert Elementary School in New Orleans - which had been under water for 28 days following Hurricane Katrina.

We learned a lot about what has been happening in the public schools and other parts of New Orleans since Hurricane Katrina.

The people who are have returned to New Orleans and stayed are still working hard. They face extraordinary challenges. They are truly inspiring.

t is truly shameful that so much more remains to be done to repair and reclaim this historically important and culturally unique American city.

[I've talked with many of you about the worsening "Support Service Crisis" about educational uses of information technology for years, but post-Katrina New Orleans has a REAL "Support Service Crisis" beyond anything we have ever feared.]

This volunteer activity was available to all registrants the day before the conference opened.
For more about this school, See:

Our excellent, amusing and conscientious leader was Troy Peloquin, a New Orleans 9th grade science teacher.

Some stalwarts did a full day, and the most stalwart of all worked outdoors scraping and sanding in the extreme heat and humidity. [ANYONE HAVE MORE PHOTOS WE CAN SHOW?]

Has anyone already produced an eClip or BHW [Brief Hybrid Workshop] about this? A BHW is an eClip + other resources. The included eClip is less than 5 minutes and the total BHW is less than 15 minutes. More about eClips & BHWs

Seems like a wonderful idea to offer volunteer options the day before or after ANY conference in any city! Great way to learn more about the city and to develop constructive relations between visitors and locals.


Additional photos BELOW were selected from postings by Barbara "Bee" Dieu in Technorati posts and Flickr posts with the tag "merlot2007onlap" [with her "Warm regards from Brazil"]

For more about MERLOT Int'l Conf 2007, see D. W. Proctor's blog: "ProEd Portal"