Response to: ‘The methodology in the paper by Chambers et al. raises serious questions about their conclusions’

We appreciate the opportunity to respond to the critique and comments by Kulig et al. [1]. We disagree that our conclusions are not supported by the data. Kulig et al. contend that our conclusions may have been influenced by on-going litigation [1]. Although some individuals contend involvement with litigation influences cognitive outcomes there is information to the contrary [2]. Only 13 of 256 (5%) patients in our study were involved in litigation and only a few of these had initiated litigation at 6-week follow-up. We reanalysed our results excluding the 13 patients involved in litigation (adjusting for intentional poisoning) and the results did not change at any time point for cognitive sequelae (p-values 0.8–1.0), depression (p-values 0.06–0.5) or anxiety at 6 and 12 months (p-values 0.1–0.9). Anxiety was higher in less severe compared to more severe CO poisoned patients at 6 weeks (p1⁄4 0.02), similar to our previous reported results [3]. Independent of litigation, CO poisoning may cause brain injury with concomitant high rates of depression and anxiety [4]. Furthermore, most of the outcome assessments were done before litigation was initiated. Therefore our results were not influenced by litigation. Science progresses through a process of testing hypotheses, refining viable hypotheses by designing better experiments, which advance research providing further clarity of the research objectives for the next set of experiments. Every study can be critiqued where genuine criticism can be raised in an attempt to improve the design and better control the independent and extraneous variables that may influence the outcome. Then there are critiques that have an agenda and have little to do with advancing science. When such critiques are connected to the litigation process, what is being written is not necessarily for the scientific audience, but rather what may support an expert witness’s testimony and protect the legal position of that expert(s). Michaels [5] has written a most informative text entitled ‘Doubt is their Product’, which shows how litigation defending environmental toxic exposure as harmless has funded seemingly legitimate research. Michaels’ shows how reasonable scientifically-based facts are attacked by those who serve as expert witnesses because having a ‘published’ report that raises ‘doubt’ about a research finding is the pathway for the legal maneouvre commonly referred to as a Daubert Challenge, which can exclude or restrict what research can be discussed in the courtroom. Another common defense approach is to criticize research, suggesting that the findings do not differ from a known base rate and therefore the symptoms/ problems of the condition in question do not sufficiently rise above the base rate to reflect any specificity to the condition in question. Kulig et al. [1] take this very tactic in their critique of our conclusions, citing a 1993 article by Lees-Haley and Brown [6], which is one of the most often cited articles used in this type of defense (see Stern [7]). Had Kulig et al. [1] carefully read that article perhaps they would have recognized that there