article smacks of ongoing bias against people using methadone Dan Bigg, Chicago Recovery Alliance 31 October 2007 While the authors' discuss a few of the studies' weaknesses they minimize or entirely dismiss other significant and potentially lethal shortcomings thus perpetuating misunderstandings and myths. It is also unclear how much of the bias and noise in this study is from the fairly significant ways methadone for addiction treatment is practiced in the Canada versus the US. A discussion of this would have also avoided such confusion.The authors describe the "triple-check" system of making up methadone doses as a perfect system of control, which is unknown by this author, and don't even bother to use their own checking system on doses before they leave the pharmacy thus missing a potentially critical source of error. In general, despite numerous competing explanations including creative and effective self-dosing patterns they conclude all sources for "discrepancies" in predicted versus "actual" dose is due to "tampering" by clients. I find this demeaning and scientifically naive, anti-methodical, and exposing a lethal bias against persons using methadone. The authors do not even make an attempt to ask clients about their explanations for differences in dose in a way which could elicit accurate information. It remains a blaring omission of explanation that one client returned with more methadone than they were given -- yet another example of the crazy silence this article covertly demonstrates with people using methadone.None of the discussion in the article suggests alternative explanations which deviate from their "tampering" theory. Such narrow vision benefits no scientific pursuit and adds only bias and smear to a field greatly needing neither.Finally, while I am sure some diversion of methadone treatment milligrams occurs I am even more sure that methadone used for addiction treatment is not the source for significant lethal street methadone even based on a study by the US Drug Enforcement Administration itself: http://www.deadiversion.usdoj.gov/mtgs/drug_chemical/2007/methadone_gfeussner.pdf I am surprised the review process did not pick up on these limitations and/or outright bias of this article. Competing interests I have no competing interests or conflicts in this case.