Graphic Methods for Presenting Facts
Circles of different size should never be compared. Horizontal bars have all the advantages of circles with none of the disadvantages
as most of the authorities on statistical work recommend. If the figures were not given, the reader would be forced to fit the left-hand circle into the right-hand circle on an area basis, or else make a ratio between the diameters and then square the ratio. Either process is almost impossible to accomplish and there is
GRAPHIC METHODS
o o
0)
MINISTRY
LAW MEDICINE EDUCATION BUSINESS PUBLIC SERVICE
o o
0)
MINISTRY
MEDICINE EDUCATION BUSINESS PUBLIC SERVICE
Independent
Fig. 39. Proportion of College Graduates in Different Professions in 1696-1700 and
in 1 896- 1 900
Charts of this kind with men represented in different sizes are usually so drai^Ti that the data are represented by the height of the man. Such charts are misleading because the area of the pictured man increases more rapidly than his height. Considering the years 1696-1700, the pictured minister has about two and onehalf times the height of the man representing public service. The minister looks over-important because he has an area of more than six times that of the man drawn to represent public service. This kind of graphic work has little real value
no necessity of inflicting such cruelty on a reader. Though the circles in Fig. 37, drawn on a diameter basis, exaggerate the ratios, the circles in Fig. 38, plotted on an area basis, make the reader underestimate the ratio. Comparison between circles of different size should be absolutely avoided. It is inexcusable when we have available simple methods of charting so good and so convenient from every point of view as the horizontal bar.