I am unable to find that text in the article. I am even unable to find the word &#x27;operator&#x27;.<p>In any case, I pointed out that there&#x27;s a 3x difference between two houses, so I am in complete agreement with that statement. My post asks a different question, which is, what is the error range on the observed results? What are the odds that the stove doesn&#x27;t actually have an effect on wood use, but that some other factor (&#x27;operator and the conditions of use&#x27;) resulted in the observed differences?