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Posts: 2
Reply with quote  #1 
In the lovely sample dashboards at the end of the book (the CIO Dashboard and the Telesales dashboard on pages 197 and 199) Mr. Few used a graphic element that is at least as complex as a bullet graph, but isn't described anywhere (neither in the book nor any place I can find online).

What is this type of graph called, and how does one read it? The response time graph appears to encode six different values: the upper limit of the acceptable range, begin/end of the thin part of the range, begin/end of the thick part of the range, and a white bar. What do the latter five values represent?

Posts: 853
Reply with quote  #2 
The Response Time graph that appears in the bottom left corner of the CIO Dashbaord is an example of a box plot. You'll find a description of box plots in Chapter 6, beginning on page 141. The sections of gray that appear in the background represent the acceptable range of response time for each system (DW, etc.). For example, it is acceptable for data warehouse response time to take as long as three seconds, but anything longer is considered unacceptable. The box plot shows that response time for the data warehouse is performing poorly, with more than half of all transactions taking longer than three seconds, extending all the way up to over 11 seconds for some. This graph allows us to see six pieces of information about response time for each system: 1) the acceptable range of response time (the gray background region), 2) the response time for the fastest transaction (the left end of the horizontal line, 3) the length of time taken for all but the fastest 25% of transactions (the left edge of the box), 4) the median response time (the white break in the center of the box), 5) the length of time taken for the slowest 25% of transactions (the right edge of the box), and 6) the slowest response time (the right edge of the horizontal line). This graph presents all of this information for each of the four systems in a way that makes it easy for us to quickly monitor and compare the performance of each.

Stephen Few

Posts: 2
Reply with quote  #3 

My bad. Thank you for the clarification!
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