Hutchinson and Lebedev have chosen to ignore an essential paragraph on page 1058 of our article. With respect, we quote part of it here again: “It is difficult to demonstrate directly that a group of individuals constitute a cluster in time and space with respect to a disease. In addition to the obvious problem of ascertainment bias associated with the retrospective identification of such groups and the difficulty of defining a suitable control framework for the purposes of comparison, there is a major logical barrier to our attempt to prove the hypothesis that the group constitutes a meaningful cluster.”
Ajit Kumar, Susan Calne, Michael Schulzer, Edwin Mak, Zbigniew Wszolek, Chris Van Netten, Joseph K. C. Tsui, A. Jon Stoessl, Donald B. Calne. On the Use of Clusters to Determine Environmental Influence on Disease—Reply. Arch Neurol. 2005;62(2):331–332. doi:10.1001/archneur.62.2.331-b
* * Maintenance Notice * *
Maintenance will be performed from 11:00pm CT December 16, 2017 to 4:00pm CT December 17. Please be advised that your site/services may be periodically unavailable during this maintenance window.