Definite thumbs up on the article from me
. Here's an old thread I started talking about it, if anyone is interested:
https://www.drmcdougall.com/forums/viewtopic.php?f=1&t=48494.
Also, here's an interesting study looking at observer-bias due to lack of blinded researchers:
http://www.bmj.com/content/344/bmj.e1119.long. This is a meta-analysis of many trials, where in each trial both blinded and unblinded researchers assessed the results of an intervention, labeling the intervention as either successful or unsuccessful. There was significant observer bias found across the trials, and this bias was caused on average by only 3% of patients being miss-categorized.