Simple Simon says

Simon Chapman's latest confrontation with reality has attracted the attention of Redheadfullofsteam who has written a nice takedown, as ever. Simple Simon is continuing his war against e-cigarettes (which has already become a "hey, we still don't know so let's keep them banned in Australia" rearguard action against e-cigarettes) by resorting to numerology.

It would be genuinely interesting to know whether this guy is as stupid as he seems or if he merely assumes that the people he needs to persuade are as stupid as he hopes. His line of attack on Robert West's recent study in Addiction, which showed that smokers were around 50% more likely to quit using e-cigarettes than if they went cold turkey, begins by accurately describing the research:

It found 93 out of the 464 people who used e-cigarettes were successful (20%), while 194 out of the 1,922 people using nicotine replacement therapy made it (10.1%), and 535 out of 3,477 of the people trying to quit unassisted did so (15.4%).

Almost incredibly, he concludes with the following words:

...headlines about the English study should probably have said there were nearly six times as many smokers who quit without any assistance than vapers who did.

As used to Chapman's cretinism as I am, this still leaves me gobsmacked. Let me explain in words that even he will understand.

This study involved a self-selecting sample. Sorry, have I lost him already?

Let's try again.

This study looked at people who had chosen their own way of quitting. Nearly 3,500 smokers attempted to quit cold turkey. Only 464 tried e-cigarettes. What matters is what proportion of each group successfully quit. A significantly higher proportion of the e-cigarette group successfully quit. By looking at the percentages in each group, we can see which method was most successful.

The fact that there were more quitters—in absolute numbers—in the cold turkey group is a reflection of the fact that there were many more people in it to start with. That isn't the point. The number of people who attempt different methods can be changed over time and policy can help do that. The obvious conclusion from this study—to anyone who has eyes to see—is that if the number of people who chose to quit smoking by using e-cigarettes was as large as the group that currently uses the less efficacious method of cold turkey, there would be many more people successfully quitting. Growing that number requires encouraging people to use e-cigarettes rather than banning them, disparaging them and over-regulating them. In other words, it requires doing the opposite to what puritanical statists like Chapman instinctively want to do.

I hate to patronise you, dear reader, with this explanation, but it seems that there is at least one person on the planet who cannot tell the difference between relative numbers and absolute numbers.

Except that we know that Chapman does understand relative numbers. We know this because he has spent most of his long life championing the dubious epidemiology of passive smoking and the relative risks it reports. He knows better than anyone that if absolute risks were accurately reported in countries with relatively small populations then "journalists will be hardpressed to write anything other than 'Official: Passive smoking cleared - no lung cancer".

Nevertheless, the great sociologist scoffs at the e-cigarette study by focusing on the absolute numbers:

Let’s look at these numbers another way. In this large study, 80% of smokers trying to quit by vaping were still smoking compared with 84.6% of those [who] tried to quit on their own. That hardly looks like a champagne-popping difference deserving the accolades abounding in narratives about vaping.

What he's saying here is that most of the smokers failed to quit. 80%, 84.6%, what's the difference?

Consider using that logic with Chapman's beloved passive smoking theory. Here, if you wink one eye, ignore statistical significance and exclude the studies you don't like, you find a lung cancer risk from a lifetime's secondhand smoke exposure of about 1.20, which is to say 20%.

What's a nonsmokers' lifetime risk of getting lung cancer? It's about 1%.

What does an increased relative risk of 1.20 from passive smoking look like? It's about 1.2%.

So, to put it in Chapman's terms, 99% of the unexposed group don't get lung cancer and 98.8% of the exposed group don't get lung cancer. This small difference of 0.2% "hardly looks like a champagne-popping difference deserving the accolades abounding in narratives about" smoking bans, does it?

Same logic, same rules, but now the crank finds himself having to attack observational studies, rather than glorify them, and so the interpretation changes.