Sometimes the most interesting discussion on a blog goes on under the radar, in comments or other off-the-grid discussion. Chris Fleming’s passing reference to research revisiting the findings of the venerable RAND Health Insurance Experiment sparked a comment by Joseph Newhouse, the Harvard economist who has published repeated analyses of the RAND experiment throughout the past quarter-century. (Newhouse and colleagues’ response is to be published in the Journal of Health Politics, Policy and Law.) John Nyman, the University of Minnesota economist whose work in the context of the Rand experiment was mentioned in Fleming’s original October posting, in turn posted a response to Newhouse and colleagues on his own Web page. Today Newhouse has posted yet another response to Nyman. He writes:

“John Nyman argues that the effect on health care use and spending found in the RAND Health Insurance Experiment is an artifact of greater voluntary attrition in the cost sharing plans relative to the free care plan….His argument is implausible.”

The twelve-page response by Newhouse and colleagues goes on to detail the reasons why. Instead of summing up the discussion here, we refer interested readers to the various components of this exchange, which might otherwise have escaped Health Affairs Blog readers’ notice as the debate appeared in the comments of a largely unrelated blog posting.