Elementary Statstics

5.2.5.5 Limitations of Diagrams and Graphs

Although diagrams and graphs are  powerful and effective media for presenting statistical data, they are not under all circumstances and for all purposes complete substitute for tabular and other forms of presentation. The well trained specialist in this field is one who recognise not only the advantages but also the limitations of these techniques. He knows when to use and when not to use these methods and from its repertoire is able to select the most appropriate form for every purpose. Julin has beautifully said, “Graphic statistics has a role to play of its own; it is not the servant of numberical statistics, but it cannot pretend, on the other hand, to precede or displace the latter”.

The main limitations of diagrams and graphs are

1. They can present only approximate values.

2. They can approximately represent only limited amount of information.

3. They are intended mostly to explain quantitative facts to the general public. From the point of view of the statistician, they are not of much help in analysing data.

4. They can be easily misinterpreted and, therefore, can be used for grinding one’s axe during advertisement, propaganda and electioneering. As such as diagrams should never be accepted without a close inspection of the bonafides because things are very often not what they appear to be.

5. The two-dimensional diagrams and the three-dimensional diagrams cannot be accurately appraised visually, and, therefore, as far as possible their use should be avoided.