{"id":1982,"date":"2015-03-29T17:57:45","date_gmt":"2015-03-29T16:57:45","guid":{"rendered":"http:\/\/www.theusrus.de\/blog\/?p=1982"},"modified":"2015-03-29T17:57:45","modified_gmt":"2015-03-29T16:57:45","slug":"the-good-the-bad-022015","status":"publish","type":"post","link":"https:\/\/www.theusrus.de\/blog\/the-good-the-bad-022015\/","title":{"rendered":"The Good & the Bad [02\/2015]"},"content":{"rendered":"

Yes, it’s been a while since the last post, but hey – isn’t it a good sign that I presumably do not stumble over too bad graphics every day (or I just might not have the time to write about it …)<\/p>\n

This example comes from SAS’s online manual<\/a> on their Visual Analytics tool. And here it is:<\/p>\n

\"\"<\/p>\n

“The Bad” is even supported by explanatory text:<\/p>\n

“This example uses a butterfly chart to show the actual sales compared to the predicted sales for a line of retail products. The butterfly chart is useful for comparing two unique values. In this chart, the two values are arranged on each side of the Y axis.<\/em>“<\/p>\n

I am sure that my friends<\/a> at SAS<\/a> know better, so I won’t start bashing here, and I will also not start to refine the plot to perfection, as the problem seems to be too obvious:<\/p>\n

Why comparing continuous quantities not side by side on the same scale, but put them on\u00a0separate, opposite scales – especially when we look at quite small differences? <\/em><\/p>\n

Maybe the programmers of SAS VA or the writers of this online help are too young, so they might have missed Bill Cleveland’s “The Elements of Graphing Data<\/a>” from 1985, but they could have stumbled over this 1985\u00a0paper<\/a>\u00a0(available on todays internet). This paper is\u00a0an essence of what the book talks about in all of Chapter 4 “Graphical Perception”, which has not changed the last 30 years (which can not be said about Figure 3.84 on page 216 ;-).<\/p>\n

So here is Cleveland’s advice on the precision of perception tasks:<\/p>\n

\"\"<\/p>\n

And here is the same data on a comparable scale – I hardly dare to call it “The Good”:<\/p>\n

\"\"<\/p>\n

If someone supplies the ggplot<\/a> “solution”, please feel free to comment and I will add it to the plot.<\/p>\n","protected":false},"excerpt":{"rendered":"

Yes, it’s been a while since the last post, but hey – isn’t it a good sign that I presumably do not stumble over too bad graphics every day (or I just might not have the time to write about it …) This example comes from SAS’s online manual on their Visual Analytics tool. And […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1,5,6],"tags":[],"class_list":["post-1982","post","type-post","status-publish","format-standard","hentry","category-general","category-the-good-the-bad","category-tools"],"_links":{"self":[{"href":"https:\/\/www.theusrus.de\/blog\/wp-json\/wp\/v2\/posts\/1982","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.theusrus.de\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.theusrus.de\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.theusrus.de\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.theusrus.de\/blog\/wp-json\/wp\/v2\/comments?post=1982"}],"version-history":[{"count":5,"href":"https:\/\/www.theusrus.de\/blog\/wp-json\/wp\/v2\/posts\/1982\/revisions"}],"predecessor-version":[{"id":1987,"href":"https:\/\/www.theusrus.de\/blog\/wp-json\/wp\/v2\/posts\/1982\/revisions\/1987"}],"wp:attachment":[{"href":"https:\/\/www.theusrus.de\/blog\/wp-json\/wp\/v2\/media?parent=1982"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.theusrus.de\/blog\/wp-json\/wp\/v2\/categories?post=1982"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.theusrus.de\/blog\/wp-json\/wp\/v2\/tags?post=1982"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}