Pie Charts Essay examples -- essays research papers

Pie Charts An important part of decision making is having a clear understanding of the information used to base decisions from. Charts can be valuable when a need to represent numerical data would benefit communicating information visually. Some of the most important aspects of a good chart are to select the right type of chart (or graph) that can best characterize the data, also, to keep the design simple in order for an audience to easily understand the information. One of the most popular types of charts is the pie chart. The pie chart is used to visually represent the proportional value of individual parts to the whole. As the name describes, this is done by representing the numerical equivalence of each part as a piece of the whole pie, which in total equates to 100%. The Pennsylvania Department of Health (2001) says that pie charts are a good choice when a relatively small amount of parts, perhaps 3 to 7, need to be represented. With any more it becomes difficult to notice the differences in magnitude; thus, the pie chart loses its simplicity and impact. They can only be used when a total amount is known, one such example would be an election where the total of votes received by all candidates equals 100% of the votes. Or a budget where the total amount spending is divided in to categories such as labor, facilities costs, advertising, etc†¦ which always are a part of the total. However, according to McBride (2003), the pie chart could n ot be used to show a change in spending through out a period. A pie chart shows data at one instance, like a snapshot and cannot be used to show change in data over time (para. 4). With the advent of computers, 3D graphs have become somewhat popular, unfortunately a negative aspect is that they add complexity to the image and can distort visual proportional value. It is recommended to stick with flat â€Å"2D† charts (para. 6). Pie charts these days are typically generated by computer software, as a result people forget that there is actually a little math involved. To create a pie chart Concordia University (2000) explains that you have to find the total value for the entire category being studied and calculate the percentage for each segment or part. Convert the percentage values for each segment into degrees relative to the 360 degrees in the circle. (For example, 12% X 360 degrees = 43 degrees). Then, Draw a circle and d... ...chart should look like with the exception of one rule, the pieces were not arranged from largest to smallest in a clockwise manner. The sizes are mixed, making less clear the relative proportions of the pieces. Pie charts can be an excellent tool for presenting information in a simple, visual and comprehensible manner. If used in the right situation and best practices are followed, the pie chart may be the tool that most influences a decision. References Pennsylvania Department of Health. (2001). Pie charts and pictographs. Retrieved January 24, 2005 from, http://www.health.state.pa.us/hpa/stats/ techassist/piechart.htm Concordia University. (2000). Pie chart. Retrieved January 31, 2005 from, http://web2.concordia.ca/Quality/tools/21piechart.pdf Sykes, A., & Smith, B. (1999). Getting started – A simple pie chart. Retrieved January 31, 2005 from, http://www.causeway.co.uk/tutorial/rainpro/apl99/dyalog/start.htm Hodges, M. (2004). Grandfather economic report series. Retrieved January 31, 2005 from, http://mwhodges.home.att.net/fed_budget.htm Perlman, H. (2003). Where is earth’s water located? Retrieved January 31, 2005 from, http://ga.water.usgs.gov/edu/earthwherewater.html