Innovations in Lines and Boxes
This is the first box plot, created by Mary Eleanor Hunt Spear, and published in 1952 in her poplar data visualization textbook Charting Statistics. A box plot describes the distribution of a set of values, drawing a box from the twenty-fifth to the seventy-fifth percentile, with a line in the middle showing the median. A vertical line is extended from each side of the box to the minimum and maximum. Until recently, Spear wasn’t credited with the development of the box plot. For decades, credit went to statistician John Tukey who published them in 1977. A campaign by the data visualization community has started to fix this and the Wikipedia page for box plots has been revised. The British Royal Statistical Society has named a data visualization contest in Spear’s honour.
Sparklines are small line charts, with no axes or coordinates. They highlight patterns of change rather than specific values. Though sparklines had been used in brain imaging for decades, the term was introduced by Edward Tufte in 1983. Human brain imaging began in 1924 with the invention of the electroencephalogram, a method of recording the electrical impulses in the human brain (commonly known as ‘brainwaves’). The of patterns of change in the impulses are more important than specific values, which vary widely from person to person. Because of this, sparklines became the standard way to display this kind of data. The first edition of the standard textbook in the field, Fundamentals of Electroencephalography (1971), had a small ECG sparkline on its cover and this 1978 edition enlarged it into a cover-spanning set of golden sparklines.
