Issue link: https://www.massageandbodyworkdigital.com/i/68012
APPROACHING GRAPHICS, AVOIDING PITFALLS If a column chart can be thought of as a snapshot, then a line chart can be thought of as a movie—it can show how a trend forms. In the last article ("Reading Charts and Graphs," Massage & Bodywork, January/ February 2009, page 126), we began exploring how text and graphics fit together in describing the results of a study. Here, we will take a deeper look at kinds of visual representation and what they express, in order to see what information needs are best met by which kind of graphic. We will focus on three of the most important and commonly- used charts, using results from a fictional massage clinic. COLUMN CHARTS AND BAR CHARTS Column charts and bar charts are frequently used to compare different categories or individuals at one point— snapshots of how variables compare at particular moments. The height of the columns represents the values of the categories being compared. Image 1 compares reported pain scores for five individuals in a massage clinic. The five individuals are listed along the x-axis—the horizontal line at the bottom of the graph. The y-axis—the vertical line at the left of the graph—shows the columns' values. To compare Terry's pain scores to Naomi's, you can look at the x-axis and find Terry's name. The red bar for Terry (the before-massage score) is at the height of 6.5 on the y-axis. Similarly, finding Naomi's name on the x-axis provides a red bar with a height of 8 on the y-axis. Naomi reported more pain (8) before the massage than Terry reported (6.5). visit massageandbodywork.com to access your digital magazine 129