Whenever we deal with large amounts of data, one of the goals for analysis is,
How is this data distributed?
This is where a Box plot can help. According to Wikipedia, a box plot is a convenient way of graphically depicting groups of numerical data through their five-number summaries: the smallest observation (sample minimum), lower quartile (Q1), median (Q2), upper quartile (Q3), and largest observation (sample maximum) [more]
Quartile?!? What is that like?
When we say $ 39,000 is the lower quartile of salaries paid in Acme inc. it means, 25% of people make less than or equal to $39,000
Like that Median (Q2) means half the samples are lower than median & the other are more than median.
Example Box Plot
Here is an example box plot depicting salaries of all analysts in USA as per our recent Excel Salary Survey.
The box shows distribution of middle half of data (salaries) while the lines (called as whiskers) show minimum and maximum salaries.
As you can see, 50% of the analysts make between $46,000 to $75,000 while the min is $10k and max is $160k.
Why use Box plots?
Box & whisker plots are an excellent way to show distribution of your data without plotting all the values. They are easy to understand. We can use them whenever we have lots of data or dealing with samples drawn from larger population.
Creating Box plots in Excel – 9 step tutorial
Despite their utility, Excel has no built-in option to make a box plot. Of course you can make a 3D pie chart or stacked horizontal pyramid chart. Lets save them for your last day at work and understand how to create box plots in Excel.
Step 1: Calculate the number summaries
Assuming your data is in list use formulas MIN, MAX & PERCENTILE to calculate summaries like below:
To calculate 25th percentile (Q1) use = PERCENTILE(list, 25%)
Step 2: Make a bar chart from Q1, Median & Q3
Just select the 25th percentile, median & 75th percentile values and create a bar chart.Make sure that your chart shows 3 different colored bars not 3 bars in one color.
Step 3: Set series overlap to 100%
Select any bar, press CTRL+1 (right click > format series) and adjust series overlap to 100%
Step 4: Adjust series order so that you can see all the bars
If you cannot see all the bars, right click on chart, click on “Select data”.
Now, adjust the series order using arrow keys so that you can see all the bars. See this demo:
Step 5: Make 25th percentile (Q1) bar invisible
Select the bar corresponding to Q1 and fill it with white color. If you make it transparent, it will not work. So make it all white.
Step 6: Add error bars to Q1 & Q3 series
Just select Q1 (25th percentile) bar and add error bar (any type) from layout ribbon.
Repeat for Q3 series as well.
Step 7: Set up error values in your data
Add an extra column in your data area and use simple formulas to calculate error values, like below:
Step 8: Set up custom error values for Q1 & Q3
Select the error bar for Q1 (25th percentile) and,
- Press CTRL+1 to format them
- Enable only minus (negative) error bar with no cap.
- Select Custom as error amount and point to the calculated value.
Repeat for Q3, but choose positive error bar instead.
Step 9: Format the box plot to your taste
Remove any legend, axis, labels that you do not need. Change colors to suit your taste and mood. Make the whiskers subtle and knock off the grid lines. You are good to go.
Making Box plots interactive
Since box plots are very useful to understand distribution of values, we use them in dashboards etc. Naturally, you are interested to know how values are distributed for various things.
In this example, we may want to know how analyst salaries compare with manager salaries.
To make things complicated, we have 10 different job types, thus enabling 45 possible comparisons (10c2)
This is where interactive box plots can help. See this demo to understand:
Interactive Box plot in Excel – a Demo
How to make interactive box plot in Excel
Construction of box plot is same as mentioned above. The difference is in adding interactivity.
Step 1: Use combo box form controls to capture comparison criteria
Excuse the tongue twister. Using Developer ribbon > Insert > Form controls, add 2 combo box controls and point them to the list of job types.
Lets assume that these combo boxes are linked to cells D1, D2.
[Related: Introduction to Excel Form Controls]
Step 2: Calculate 5 number summaries using MINIF, MAXIF and PERCENTILEIF formulas
Don’t rush to type the formulas yet. There is no such formula as MINIF (or MAXIF or PERCENTILEIF). Assuming your list of jobs are in joblist, write
=MIN(IF(joblist=”Analyst”, list_of_values,””))
and press CTRL+Shift+Enter
Using MAX(IF(…)) and PERCENTILE(IF(…)) you can calculate remaining 4 summaries.
Step 3: Based on combo box selection, fetch any two sets of values
Using INDEX formula, we can fetch values corresponding to each combo box selection to a set of cells, like this:
Step 4: Connect these values to your box plots
That simple!
Step 5: Format and interact
Format the charts. Play with combo boxes to interactively compare one set of distribution with another. Show it to your boss or client and see them fall off a chair.
Download Box plot tutorial workbook
Click here to download the workbook containing these examples. Play with it. Check out various formulas and chart settings. Learn.
Do you use Box plots?
I love box plots. I have used them several times. Few examples are here: Excel age survey results, Gantt box chart and more.
In our Excel salary survey contest too, many people have used box plots to clearly compare compensation composition. Checkout the entries by Aditya, Allred, Anchalee, Anup, Bryan, Jeanmarc, Joerg, Kostas, Luke, Michael, Nathan, Sergey and Vishwanath. Especially Jeanmarc used interactive version of box plots to allow comparison on demand.
What about you? Do you use Box plots often? How do you prepare them? What is your experience like? Please share using comments.
Create Box plots often? Use Jon’s Add-in
If you need to create box plots often and find the above process tedious, then please consider getting a copy of Jon Peltier’s Box Plot add-in for Excel. It works like a charm and produces what you need. All in a few clicks. Click here to know more.
PS: Link to Jon’s add-in is an affiliate link. It means, when you buy it from Jon thru this link, I will get a few bucks too. I recommend it because I know it is awesome and perfect for box plots.
37 Responses to “Pie of a Pie of a Pie chart [Good or Bad?]”
If I could have the same quality of graphics and illustration in Office Apps, I would certainly use it.
If I could have the same quality of graphics in Office Apps (Excel, PPT) I would certainly use it.
Chandoo,
First, let me say I love your blog. I like this post, and I think that technically (in terms of readability of data) your argument is correct. The bar of bars, and the table, are much better for readability and accuracy, and as you say would be much easier to produce.
But these points ignore the context of the chart. If the chart was part of a scientific paper, your solution would be a valid one. The context in this case is an illustrated atlas of wildlife. A companion graphic to go with written text. The importance of aesthetic goes up over readability and accuracy. Much of the data and points (I assume) will be covered in the text.
There's always a pure technical tufte-esque argument. But I sometimes think it ignores the value of aesthetics. (Which I admit are quite subjective)
Great post though. Thanks.
The Treemap makes the scope of the data much clearer! The 3D pie chart depiction is deceptive.
This reminds me of the videos ive seen on the internet where it compares the relative sizes of the earth with the larger planets, then the sun, then other stars in the galaxy. Eventually there is an image showing the largest star in the sky with a little pixel representing the sun.
My point is if you varied the size of the charts it would help convey the message. The first chart (salt vs fresh) would be the biggest and the rest would be arranged in descending order. I feel this would be more accurate.
It may be helpful to consider the advice of Steven Few and Edward Tufte regarding pie charts in general. To summarize, they are seldom the most useful way to present data. Here's Few's thoughtful piece on the subject.
http://www.perceptualedge.com/articles/08-21-07.pdf
Try putting the percentages on the bar charts instead of actual amounts. Lakewater would be .013 % instead of 52.
That is very good pie chart example.
Please send example file if it is possible.
It will work , even though colors may be confusing , it can be labeled well . Also it can be called as the drilled chart , as it drills in information further , like the first chart may show business in a region , second may drill into a particular region , thrid may further drill into wat products are there in that region . It works well for me , i would more vote for the 2 nd option .
Overall all this site is awesome ,
p.s : just like me
The risk with pie of a pie of a pie chart is that Jon may have a seizure by looking at it. Also, it isn't easy to read. 😉
I dunno. The only thing worse than a pie chart is a cascading series of pie charts. I don't even think they really lend themselves to this sort of thing. It just becomes a big hide-the-ball game with your viewer.
Those goofy connectors between the pies are pure chart junk. I can't really tell if the second chart has 2 series or 3 - because the connector is a different color than the 2 labeled slices. Despite that, even whereas the drill down kind of works, still the individual components suffer from the same old weaknesses that 3d pie charts have.
Use a large bar chart as your "cover story", and fill in the sub points with smaller bar charts - or even go grab the Fabrice SFE project for extra butter. Use page orientation, color, and some text styles to guide your audience through the drill downs.
FWIW, if you check out the guy's site, you can find several other truly mortifying charts:
http://www.andrewdavies.com.au/index.html
The methane emissions one is particularly heinous. Although, I'm kind of debating what I think about the 'Glacier Changes" chart. I'd kind of like to see the data on that to see how it would look in a more traditional horizon chart.
Thank you, that was scary. I don't understand the "Glacier changes" Chart at all...
Its a very nice way to represent the data, especially when we have sets and sub-sets within the data.
I like these!
Except for the fact that they aren't dynamic and hence must be setup manually each time
It would also be nice if they could be interrogated as in select a different segment and the new data falls out automagically, but then none of the standard Excel charts do that either.
I'd like it better if the bars were stacked. How about this idea (I hope I can convey it in words):
First bar is vertical and stacked.
Second bar is horizontal, stacked horizontally and the same proportion had it been on the first bar.
Third bar is vertical, stacked vertically and the same proportion had it been on the second bar.
Then it would really look like you are zooming on the chart, like the Powers of Ten video, or maybe like the golden ration spiral.
These looks shunting but setting up for each step makes kicks them out. However if these can be arranged automatically by native excel or by VBA, these will be the part of my "Archery"
I agree with Chandoo's Suggestion about the Bar Graph which represents data in a very appropriate manner. Even I prefer doing the same. I seldom use Pie Chart unless required.
That's a real nice example of a missleading infographic. But to be honest, I think chandoos suggestion is not much better!
Why are pie charts bad? I think because they don't show the real size-relations. The biggest pie in that example ist 300k big. The 2nd one has only the size of 10k, about 3% of the first one. Niether the pies nor the bars show the real sizes. I jnow, it's hard to show the sizes because the values of the second and the third pie are so small. But that's what visualization are about - showing relations to allow the reader to see the real sizes!
So how to show the real figures?
First possibility is o use a 1:1 scaling. Well then, you need a very big screen to show also after a 90° rotation, wihich I would prefer because it's a structural comparison and not a timeline. Maybe that solution is not the perfect way.
The other chance you have is to zoom in but to really show that you zoom in! http://www.pro-chart.de/images/Water_Fall.png maybe gives you a first impression what i mean. (i was a quick try, done in 10 minutes)
The next way is, maybe to fold the bars like in the financial report 2011 of the Post of Switzerland page 22. That chart is based on an excel chart. Maybe can explain you how to do it 😉
Financial Statement: http://www.post.ch/en/post-startseite/post-berichterstattung/post-berichterstattung-service/post-berichterstattung-downloads/post-gb-2011-finanzbericht.pdf
page 22: http://www.pro-chart.de/images/FS_Schweizer_Post.png
A way that is not so very common is to divide the bars in a lot of single datapoints. So maybe the 390k bar then consists of about 5,000 single datapoint. That's not possible - it is! Have a look:
http://www.pro-chart.de/images/Dotted_WF.png
It's pure excel!
Now one single point ist 0,2% of the whole (in the example above). Add more datapoints and you can visulize the very big and the very small numbers!
Wish you a lot of fun - visualizing with excel can be very powerful!
Joerg
...if you would like to know how these charts work, just send an email to J.Decker@pro-chart.de
Hey Joerg,
I don't dig so much the dotted waterfall thing. But this is kind of awesome:
http://www.pro-chart.de/images/FS_Schweizer_Post.png
Can you help me on the bar of bar graph? Would it be possible to create that from pivot table? Can you show me how to create the bar of bar graph?
do nothing but say "Awesome!"
You are a Rock star.....This seemed an answer as if someone was reading my mind and just had the solution to my questions on what I exactly was looking for .....What a Fab !!
can u explian me step by step
Can anyone please explain how to make this chart please.
Do you mean the pie of a pie chart or the folded bar chart?
Joery PIE OF PIE Chart please
Can someone please explain how to make PIE OF PIE Chart.
@Mandeep
The last line of the post is:
PS: If you want to know to create this pie of pie of pie chart in excel, see here.
Due to forum migration, link is now:
http://chandoo.org/forum/threads/multiple-pie-chart.7343/
Hi... i love these charts.... can any one show me how to draw these charts in excel 2010
@Vamshi
The very last line of the post refers you to:
PS: If you want to know to create this pie of pie of pie chart in excel, see here. http://chandoo.org/forums/topic/multiple-pie-cahrt
Where is the attachment....it used to be there...i have seen this before but now i am not able to find...
See this:
http://img.chandoo.org/playground/WaterDistribution-chandoo.xlsx
And this:
http://chandoo.org/forum/threads/how-do-you-create-this-chart.9743/
Normally I don't learn post on blogs, however I would like to
say that this write-up very compelled me to try and do so!
Your writing style has been amazed me. Thank you,
quite great article.
This is very impressive, I would like to learn how to build this for myself. I have tried for some time now, is there a step by step process on how to create these waterfall pie of pie charts?
I am novice to excel and use it very seldom. But your blog contains to the point information one needs to get going.
I was searching for a trick to do a Pie chart drill down - for example the first pie chart shows how the prices are distributed between perishable and non-perishable items.
Now if we want to know how the perishable items are distributed - one can click the segment and it will draw another pie chart with distribution of all different perishable items (milk,meat,fruit,veg etc)
So do you have any such trick?
Regards,
electrojit
I like the look of your pie of pie of pie chart, although I understand that the relative size of each pie does not represent the actual percentages.