Putting aside all the problems of confounding effects anti-F people ignore with such plots his claim is just hand waving. He does nothing to test his claim and yet it would be so easy – measure the slopes of the plots for each group of countries. Despite the huge problems of the data I did this and found the slope of decay rates was -0.13 for the unfluoridated countries and -0.17 for the fluoridated.

That represents an extra decline in decay rates for fluoridated countries of around 30%. Now that doesn’t take account of the improvement in the earlier times before data was taken. So it under-represents the true improvement due to fluoridation.

So be careful of Connett’s hand waving. Even with the crappy data and confounding effects his plots actually don’t say what he claims.

The post Fluoridated and unfluoridated countries graph appeared first on Making Sense of Fluoride.