Author here. Thanks for setting the context: Datawrapper – the data vis tool I write articles like this for – is indeed for people who want to make a point with their charts and maps, often to a broad audience. I agree that people who have learned to read dual axis charts can benefit greatly from them (the same is true for rainbow color maps).
Financial Times journalist John Burn Murdoch changed my mind on dual axes charts – even for casual readers! – a bit over the last six years, too. Here's a dual axis chart he created for the FT: https://x.com/AlexSelbyB/status/1529039107732774913
The next article I write on dual axis charts will probably be a "What to consider when you do use them" one.
At first glance, sure, but without further context or supporting data I'm suspicious:
1. Why just the Daily Mail? Is that the only paper that matters in Britain, or just the one that happens to correlate?
2. I would expect public opinion to lag coverage in the paper if there were a causal relationship. This graph is over too great a period to really see that, but if the creator wants to convince me, they'd show that.
3. I might expect the lag to differ when coverage is increasing vs. decreasing. Again, if I'm to believe this graph, more context would help.
4. No consideration of other factors that might lead to changes in public concern?
5. No consideration of factors that might lead to *both* an increase in coverage *and* an increase in concern?
I'm sure I could come up with 5 more reasons to doubt this graph if I thought for another 60 seconds...
Financial Times journalist John Burn Murdoch changed my mind on dual axes charts – even for casual readers! – a bit over the last six years, too. Here's a dual axis chart he created for the FT: https://x.com/AlexSelbyB/status/1529039107732774913
The next article I write on dual axis charts will probably be a "What to consider when you do use them" one.