It all began with my Excel Dashboard Tutorial – Making a dashboard with player statistics. I have used bar charts with axis whose minimum is not zero, to create a dramatic effect in the charts. See below:
Jon Peltier commented saying that,
Rule #1: Bar and column chart value axes should start at zero. Since the lengths of bars and columns represent their values, starting at a position other than zero will lead to a misleading display.
As always Jon raised an excellent point. I liked it so much that I wanted to get your opinions on this axis scaling issue.
What do I think about this visualization rule ?
First the positive points about the rule:
- If you start axis at non-zero values, it gives a wrong impression about the data. In my example above you might end up thinking the top value is actually 10 times that of bottom value.
- The rule helps easy interpretation of data, since everything starts at zero.
Now the negative points about the rule:
- Not all data starts at zero (like the above with values ranging from 8000 to 12000). So when you create a bar chart for the data (why only bar charts, because they are easy to make and read) often you end up creating charts from which making out any analysis could be slightly difficult
- Breaking this rule helps in creating dramatic effect on your charts, one of the reasons we use them. Often when you use data with narrow range, creating dramatic effect could be difficult. Axis adjustments can help (you may want to try logarithmic axis scale as well)
Finally, I think this rule can be broken as long as we have right data and make alternative arrangements (like adding data labels) to ensure correct interpretation. Since this is a standard people have come to expect, it is better to make it clear to your audience about the axis range.
What do you think about the charting rule: Bar and column chart value axes should start at zero.
11 Responses
Ciao Hui,
Collecting Excel tricks under the title “Notable Excel Websites (Non-MVP) Edition” is a brilliant idea…
Thank you in the name of all The FrankensTeam.
On our site there is a box with a picture and text highlighting:
This is a no-MVP site
we think ourselves “bad boys” a bit 🙂
For those who would like to know why our site is a no-MVP site, enough to click on the link:
http://goo.gl/lxDszY
Thank you again!
Thanks a lot
I really enjoyed this (newsletter). I must admit that I rarely read an Excel newsletter (and I subscribe to quite a few) all the way though, but this grabbed my attention and before I realized it, I was engrossed in it. I must also admit that most of this I don’t understand, yet. But, it excites me when I do learn something new in Excel. I can’t wait to see how much of this I can implement into my (constantly-evolving) ‘House Budget’ & ‘Family Medical’ worksheets that I have developed over the past few years! I sure hope to see more of these type of newsletters in the future! Thanks!
Thanks for doing this Hui! I appreciate being included.
I like Tom’s tip a lot. I posted about a tool I wrote to automate this at http://yoursumbuddy.com/tables-edit-query-dialog/
EXCELLENT !
Hui, This post is Superb! More over I have always been a fan of Roberto’s work and have learnt a lot from him.
Here are some of my recent contributions
1. Customising markers in a chart – http://www.goodly.co.in/customize-markers-in-a-chart/
2. Charting Hacks to work faster – http://www.goodly.co.in/5-charting-hacks-to-help-you-work-faster/
3. 7 Date formulas to make life easy – http://www.goodly.co.in/date-formulas-in-excel/
4. Customised scrollbar using VBA – http://www.goodly.co.in/customized-scroll-bar-in-excel/
5. Adding Direct Legends – http://www.goodly.co.in/customized-scroll-bar-in-excel/
Hope everyone enjoys!
I like the Excel Ninja Menus.
1. Select a cell or range then move till the 4-way cross appears. Right-Click and drag the selection to another place in the worksheet then, like a ninja, a menu full of skills and throwing stars pops up allowing me to do all kinds of awesomeness.
2. When you click the fill box on a Date and right click and drag it down, a lot of amazing Date options pop up.
I also brand my Excel to remind myself that I’m awesome. In my personal macro workbook I place the following code.
Private Sub Workbook_Open()
Application.Caption = “SuperKrishna’s Awesomeness”
End Sub
My favorite tip goes along with #17. If you try to copy subtotaled data (and in earlier Excel versions filtered data),when you paste it all the data displays instead of just the summarized data.
To get around this, select your summarized data, click on Find and Select tab and then select Go to Special. Click Visible cells Only and click OK. Now paste and you will see that only the summarized data has been copied.
You can also go CTRL+G and then click the Special icon at the bottom of the dialog box.
What a great idea, Chandoo! I’d love to be included in your next edition:) Perhaps a VBA exclusive version?
@Ryan
I will review this concept about 6 months out from the original post and be sure to keep your site in mind
Hui…
That sounds great, Hui:) I just realized I gave credit to Chandoo for the idea and I should have attributed it to you.
Sorry about that!