220.127.116.11 Limitation of Pie Diagrams
Pie diagrams are at times less effective than bar diagrams for accurate reading and interpretation, particularly when series is divided into a large number of components or the difference among the components is very small. It is generally inadvisable to attempt to portray a series of more than five or six categories by means of a pie chart. If, for example, there are eight, ten or more categories it may be very confusing to differentiate the relative values portrayed specially when several small sectors are of approximately the same size. This type of diagram, although frequently used, appears upon comparison inferior to simple bar diagram, the divided bar diagram or a group of curves.