June 2, 2013

Submissions are for reading, not counting

The Herald, writing about Hamilton’s pending removal of fluoridation from their water supply

A Hamilton City Council tribunal examining the topic has re-ignited intense public debate on the issue, with 89 per cent of the 1,557 submissions made to it in favour of stopping fluoridation. In 2006, 70 per cent of residents who voted in a referendum backed fluoride.

This actually isn’t evidence or even a suggestion of a change in opinion. All we can tell from the numbers is that 1386 people now want fluoride removed.  Public submissions are useful qualitatively, not quantitatively.

It may be true that the people of Hamilton don’t want fluoride in their water, in which case I think they are unwise, but it’s their problem. Confusing self-selected numbers with referendum votes  isn’t going to help determine what they want, [and neither is the exclusion from voting of three of twelve council members on the grounds that they also sit on the DHB and so have thought about the issues before]

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Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »