I saw an illustration which took me a great deal of examination to comprehend. In fact, the illustration was not truly comprehensible until the data was replotted using a different charting approach. Perhaps I’m too slow in comprehending data visualizations, having so little experience in the field. I can only take solace that so many so-called visualization experts also prefer different approaches than that used in the illustration.

I have presented my reasoning for why this illustration is ineffective. The artist who produced the illustration showed how, if misinterpreted, the alternative chart is wrong. The artist has not responded to repeated explanations nor to additional examples of this approach, but instead returns to this favorite misinterpretation.

The discussion is going nowhere, so I have suspend further comments. I’ve never before felt the need to do this.

‘I think the whole tone of this blog is to show how design could better meet the big picture of getting the majority of the audience to understand your story’.

And you think by misrepresenting the line at the end of March to make it look like £35bn, when you know the figure is £14bn, helps the audience understand the story???

I showed you a whole bunch of examples where other people don’t realise this is wrong, and invited you to comment on this.

Your comeback… Perhaps you should get in contact with the Bank of England and explain to them the error of their ways But what did I actually say ? The Bank of England graph is correct, but only because they raise the base rate at exact times, leading to a stepped graph.

According to your criteria for the use of line graphs , even the Bank of England get it wrong sometimes:
http://screencast.com/t/N2ZhZDc2ZW

And I’m not sure whether this graph from you meets your own criteria:
http://screencast.com/t/MWZjZmI3Y

Or this one on unemployment from you:
http://screencast.com/t/NDViODliZ

I agree with Jon that for this particular data we’re discussing, any of the three types of chart presented (line, bar, floating bar) are acceptable.

You say the the steps are a recognition of the story, the narrative. I say the steps are recognition of one story, one narrative, and that it’s not a right/wrong choice if you choose to show steps or a line.
You say The whole tone of this blog is to show how design misses the details because the designer is too preoccupied with making things look pretty.
I think the whole tone of this blog is to show how design could better meet the big picture of getting the majority of the audience to understand your story.

I shouldn’t have been defensive? You expect me to agree with the half-read subjective ‘critique’?

I have not denounced best practices and have responded to your arguments, which, sooner or later always come back to the same point. Namely, you don’t like it because it’s, well, ‘pretty’, and anything I say is too precise for you or a distraction – it’s your blog and how dare anyone not agree with you.
So much for mutual learning.
You have complained about having to clarify things that you feel are beneath explanation. I consider all opinions and criticisms are valid no matter where they come from and irrespective of the background of the sayer.
You do not accorded me the same respect, and whether you like it or not, I do know something about what I do.
I haven’t seen any of your work but I really wonder whether a man who has a logo like yours at the top of his page has any right to talk about best practices in the visual domain

Nobody has claimed that you (nor the entirety of your business) are ignorant or fools, simply that your graphic has gone against best practices of data presentation. This made you defensive from the start. You have denounced best practices, and ignored explanations and counter arguments. This was an opportunity for discussion and mutual learning, but unfortunately you did not see it that way.

I should never have dared criticise your criticisms. Apart from making things pretty I have no grasp, nor does anyone else in my business by the look of it, about what they are payed to do. Those fools on the business desks, those statisticians, who insist on differentiation, on accuracy, on ‘microscopic’ details… the fools! Perhaps you should get in contact with the Bank of England and explain to them the error of their ways?