Subject: Braille Literacy and Employment

Date: 8/22/2022, 3:20 PM

To: Jonathan Mosen <[email protected]>

Hi Jonathan,
You asserted in episode 193 of Mosen at Large that there are studies showing employment rates of 90% for braille literate people.  Without you identifying studies of braille literacy and employment by name , I cannot review and evaluate them.  I was able to find the following study on a NFB website:
Rehabilitation and Employment Outcomes for Adults Who Are Blind or Visually Impaired: An Updated Report
By Edward C. Bell, Ph.D., and Arielle M. Silverman, Ph.D.
The authors of this study are careful to use words like correlate, correlates and association when discussing braille literacy. This word choice is important because of a core principle in both logic and statistics.  Correlation is not causation.  This means that people trying to suggest that braille literacy leads to better employment outcomes are simply wrong.  All that can be claimed is an association.
The study also has a huge methodology problem.  I could find no evidence that the authors tried to control for self-selection bias.  The survey participant recruitment method used as described in the report probably increased the likelihood of self-selection bias.  The failure to control for self-selection bias generally means for social scientist and policy researchers that the study is probably worthless for activities like public or education policy analysis.  
Best Regards,
Ken
Sacramento -- California