The following pie chart was circulating on the internet in August 2015 till political magazine Politifact came out with some explanation and reasoning behind the chart (Jacobson, 2015).
The above graph shows that military spending formed more than 57% of the total federal spending in US. The graph does not mention the time period taken, but it can be assumed to be based on latest data.
The graph caused huge furore in general public as it showed that the federal spending on food and agriculture was only 1% of the total budget. Many questioned the spending pattern of the federal government and the need for such high expenditure on military.
However, one very important aspect not presented in the above graph was regarding the base of the spending percentage, i.e. what formed the total of these expenditure heads shown. Federal spending is divided into mandatory and discretionary spending (Jacobson, 2015).
The above graph is related to only discretionary spending. Discretionary spending is done by cabinet departments, independent agencies etc. However, if mandatory spending is also included and the total spending is looked at, the expenditure on military would be roughly 16% while healthcare would form 28% of total expenditure and social security would form another 25% (Jacobson, 2015).
So the graph has a basic flaw of hiding the base number used in order to mislead the viewers. Such a flaw can be corrected through two ways. The first one relates to disclosing the computation and methodology used for the information being displayed. And the other way is to mention information regarding the differences in data when full data set is used (Huang, Huang, Wu, & Hsieh, 2011).
If the graph had mentioned that only discretionary spending is used or had it mentioned the percentage spending for total expenditure, the graph would not have been misleading.
References
Jacobson, L. (2015). Pie chart of 'federal spending' circulating on the Internet is misleading. Politifact. Retrieved from http://www.politifact.com/truth-o-meter/statements/2015/aug/17/facebook-posts/pie-chart-federal-spending-circulating-internet-mi/.
Huang, S. Y., Huang, S. M., Wu T. H., & Hsieh T. Y. (2011). The Data Quality Evaluation of Graph Information. Journal of Computer Information Systems, 51(4): 81-91.
