slide session 13 - data visualization

tufte’s principles for analytical design

• comparison

• causality

• multivariate analysis

• integration of evidence

• documentation

• content

comparison

show contrast and differences

causality

show mechanism, explanation, and systematic structure

multivariate analysis

show multivariate data; that is, show more than 1 or 2 variables

integration of evidence

completely combine words, numbers, images, and diagrams

documentation

thoroughly describe the evidence

• provide a detailed title

• indicate the authors and sponsors

• document the data sources

• show complete measurement scales

• point out relevant issues

content

analytical presentations ultimately stand or fall depending on the quality, relevance, and integrity of their _____

minimize the lie factor

representations of numbers should be proportional to the numerical quantities represented

• size of effect shown on graphic / size of effect in data

cut the clutter

get rid of chartjunk, include more vibration/the grid/the duck

traits of excellent graphics

• shows the data

• induces thinking

• avoids distorting data

• presents many numbers in a small space

• make large data sets coherent

• encourages people to make comparisons

• reveals data at dif levels of detail

• serves a reasonably clear purpose

• integrates statistical + verbal descriptions

context

present data in ___

• graphics must not quote data out of ___

data-ink ratio

proportion of a graphic’s ink devoted to the non-redundant display of data-information

• data-ink/total ink used to produce the graphic

• 1.0 - proportion of a graphic that can be erased without loss of data-information