Figure 10.19 suggests using a horizontal bar chart to rank and compare items. Some writers also use column charts for that purpose. What are the pros and cons of using horizontal bars versus vertical columns for graphs that compare items?

Figure 10.19

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PURPOSE Show how one item (100%) divides into multiple parts Compare parts of multiple items Compare multiple items according to a single characteristic Show changes over time for a relatively small number of dis- crete time periods PURPOSE Show changes over time to emphasize a trend Show how data are distributed in a se- ries of ranges Show the pattern of distribution for a continuous series of data Compare variables for a small data set Compare variables for a large data set BEST GRAPH TO USE 100% 0% Chocolate chip Purst batter 100% Column chart Compared to cakes and bread, doughnuts bring in more revenue and take less money and time to produce 15% Lanenp And co 30% D% $175 3 millier $0 #trades 250 Your 1 BEST GRAPHTO USE 35% Baker Gilman Carter Revenue Jonas 50% $0.00 30 Weight (lb) 250 300 250 200 150 Pie chart Competitor A has smallest market share Competing D 40% 112 2 J F purchaus anders 500 400 300 200 200 100 0 50 32 4 215 27.50 Column chart Return on equity declined in years 1-4 and was negative in year 5 28% 25% You 2 Compador C 65 45% Horizontal bar chart Chocolate chip Is our most popular cookle MA 55 30% Production Cost 25% 20 Years on job Line chart Year to date, actual revenue is exceeding budgeted revenue 56 Agdy Actuali $5 23% 150 50750 Your 3 Compt A 10% 92 64 107 275 Co 20% 73 29 $19.0 21 3 3.8 138 65 65 Production Time $116.20 12 348 8 SHE 4 $10.5 $127.30 MJJA 20% You 4 45% Cakes Histogram (step-column) Most stock trades last week were executed between $27.51 and $31.50 per share 325 08 35% Bread 20% Doughnuts HISTOGRAPH (FREQUENCY POLYGON) Most customer purchase orders are between $40K and $60K Height (in $27.55-529.50 $29.51-$31.50 $21.51-522.50 Pris per share Budget Revenus 10 101 10 20 30 40 50 60 70 80 90 Size of purchase order ($000) Paired bar (tornado) chart 250 12 No relationship exists between a salesperson's seniority and sales Name -15% Your 5 $14.50 SOND 135 75 SCATTER PLOT Height and weight of high school senior class 205 >$22.51 100 2 Annual sales (3000) $200.0 30 160 20 BEST PRACTICES Limit to five or fewer segments. Label each segment and pro- vide percentage values. Put most significant segment at the 12:00 position. If seg- ments are equally significant. arrange from smallest to largest Show emphasis with a darker color or by "exploding" the most significant segment. Use instead of multiple pie charts. Put the most important item at the bottom of the column so that all its component parts share the same baseline. Connect series with a line. to emphasize relationships. (optional). . Add value labels on the bars or at the ends of bars. Arrange from largest to small- est if your purpose is to rank items. Otherwise, arrange in an order consistent with your message. Use color to highlight bars you want to emphasize or to group categories of bars. Add value labels at the top of columns. Arrange chronologically to show changes over time. Make the space between the columns narrower than the width of the columns. Use color or shading to em- phasize one point in time more than others. BEST PRACTICES . Limit the number of lines if the graph is difficult to read. Provide value labels wherever possible. If too cluttered, label only select data points. Label the lines instead of us- ing a legend. Use a bright or dark color to em- phasize the most important line. Use short labels on horizontal axis. Avoid diagonal labels. Generally, use groups (buckets) of equal size, unless unequal groups make better sense. Eliminate spaces between col- umns to emphasize that data are continuous. Label the x-axis (horizontal axis) with range values. Avoid overlapping range labels such as 0-5, 5-10, instead use 0-4.9, 5-9.9. If you put value labels at the top of columns, eliminate gridlines. Do not include range labels on the x-axis (horizontal axis). In- stead, use discrete measure- ment points. Use light gridlines to help at reader interpret the values on the y-axis (vertical axis). Use light gray vertical reference ines to highlight a specific area of the distribution. Alternatively, shade the area under the rele- vant part of the curve. Plot the independent variable on the left, in a low-to-high or high-to-low sequence. (If variables correlate according to the expected pattern, the paired bars will be mirror images.) Place labels on the inside base of the bars, so that they line up vertically. Plot the independent variable on the x-axis (horizontal) and the dependent variable on the y-axis (vertical axis). Add a trend line. If variables correlate, they will cluster around that line.