Harriet Hall says:

"I formed my opinion of chiropractic the same way Stephen Barrett did…."

Here are links, that tell how Stephen Barrett formed his opinion(and some links that give a background.):   

http://buggesblogg.blogspot.se/2012/06/lite-om-en-kritiker-av-kiropraktik.html#comment-form

http://buggesblogg.blogspot.se/search?updated-min=2011-01-01T00:00:00-08:00&updated-max=2012-01-01T00:00:00-08:00&max-results=5

(Missa intr kommentarerna.)

http://buggesblogg.blogspot.se/2013_08_01_archive.html

http://buggesblogg.blogspot.se/2012/10/who-foreslar-ny-beteckning-pa-spinala.html

http://buggesblogg.blogspot.se/2013_08_01_archive.html