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Re: Publish or (gulp) Perish

  • From: Michael.Dillon
  • Date: Thu Mar 25 06:31:34 2004

>> Powerpoints have a hard time matching the depth of a refereed journal
>> submission, because with the powerpoint, soundbites tend to take
>> precedence over content.

>Attention to sidebar on page 192 of the Columbia Accident
>Investigation Board report entitled "Engineering by Viewgraphs":
>http://www.nasa.gov/columbia/caib/PDFS/VOL1/PART02.PDF

Everybody who makes slide presentations should read this.
I know it has influenced me in trying to make my presentations
clearer and shorter and more precise. If you read nothing
else from the report, have a look at this slide reproduced
below as close as possible to the way it originally appeared
including line breaks and bulleted indentation:


    Review Of Test Data Indicates Conservatism for Tile
                       Penetration
    ---------------------------------------------------

* The existing SOFI on tile test data used to create Crater
  was reviewed along with STS-107 Southwest Research data
  - Crater overpredicted penetration of tile coating 
    significantly
    * Initial penetration to described by normal velocity 
      - Varies with volume/mass of projectile(e.g., 200ft/sec for
        3cu. In)
    * Significant energy is required for the softer SOFI particle
      to penetrate the relatively hard tile coating 
      - Test results do show that it is possible at sufficient mass
        and velocity 
    * Conversely, once tile is penetrated SOFI can cause 
      significant damage 
      - Minor variations in total energy (above penetration level)
        can cause significant tile damage
  - Flight condition is significantly outside of test database
    * Volume of ramp is 1920cu in vs 3 cu in for test

The Columbia investigators zeroed in on the words "significant"
and "significantly" used 5 times on the slide with meanings varying
from "detectable in largely irrelevant calibration case study"
to "an amount of damage so that everyone dies" to "a difference 
of 640-fold." None of these 5 usages appears to refer to the 
technical meaning of "statistical significance."

They also noted that the low resolution of a slide promotes
the use of compressed phrases like "Tile Penetration" whose
meaning can be ambiguous and usually is never defined.

The slide alludes to the idea of damage to the tiles
but often avoids saying it directly referring to "penetration"
or "it" and using unclear sentence fragments.

If you do want to see the original it is on page 95 of the
PDF file linked above.

--Michael Dillon







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