While preparing a project plan, I had a strange problem. I wanted to highlight all the project tasks that fall with-in a certain date range. At the lowest level, the problem is like this:
There are 2 ranges of dates (a,b) and (x,y) and I want to know if they overlap (ie at least one date common between a,b and x,y)
The formula for testing such a thing seemed tricky at first. So I drew the conditions on paper to get clarity on what we should test. Evidently, there are 4 ways in dates (a,b) can overlap with dates (x,y) as shown below:
Now, we can test for the overlap condition using a formula like this:
If x is between a and b
or a is between x and y
then overlap
else do not overlap
As you know, there is no formula in excel like isbetween(). So we have to break it up to 2 conditions and an AND() Formula. Finally the formula becomes,
=if(or(and(x>=a,x<=b),and(a>=x,a<=y)),"Overlap","Do not overlap")
Now, it seemed like quite a big formula for testing if 2 ranges of dates overlap.
So, I continued my quest for even shorter formula.
After sometime, I realized that if we test for non-overlap instead of overlap, we can write a shorter formula.
Do not understand? Let me explain.
While there are 4 ways in which (a,b) can overlap with (x,y), there are only two ways in which (a,b) cannot overlap with (x,y). See this to understand:
Now, testing above conditions is very straight forward in excel.
the formula becomes, =if(or(y<a,b<x),"Do not overlap","Overlap")
The formula is much shorter and easy to maintain.
I was able to use it to test if a set of tasks in the project plan are running between given dates (for eg. next week). All is well in the end.
How do you test overlap conditions?
Do you ever have to test overlap conditions? What kind of formulas have you used? Please share your formula tips & tricks using comments.
15 Responses to “Make a Bubble Chart in Excel [15 second tutorial]”
Noooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo!!
Whyyyyyyyy?
The idea is to tell how to make a bubble chart. I got an e-mail from a reader recently asking how the scatter bubble is made. So I thought a 15 second tutorial would be a good idea to show this.
Did that email go "Dear Chandoo, I know that you scorn bubble charts, but if I don't do one in Excel for my boss then he'll fire my sorry ass, and my children will have to be sold for medical experiments in order for me to be able to afford the upgrade path to Excel 2010"?
If so, fair enough...it's all in the greater good 😉
Chandoo,
I am using excel 2003 and it is not working. The x axis is not the one that I enter in x axis column. Please help! Thanks.
Sorry, after few attempts, I managed to get the right result. I shouldn't select the title (header) of the table and select only the data to produce the right bubble chart.
What's wrong with bubble charts? Is there a better method for displaying scatter plots with lots of overlapping data points? Don't tell me you'd rather jitter!
@Sanwijay: Cool.
@Precious Roy: There is nothing wrong with bubble charts. Infact, it is the only way to show 3 dimensional data (x,y and sizes) without confusing your audience. Jeff is worried that people might misuse the chart. As with any chart, bubbles also have a place and time for using them.
I recommend using bubble charts to show relative performance various products in several regions and similar situations.
Also, human eye is notorious in wrongly estimating the bubble sizes (as we have to measure areas). See http://chandoo.org/wp/2009/07/28/charting-lessons-from-optical-illusions/
We can partially improve bubble charts by adding data labels, but if you have too many bubbles, the labels will clutter the chart and make it look busy.
I can't seem to find a way to plot more than ten bubbles on a chart and need to know how to add more
@KW.. why would such a thing happen. I am sure you can add more bubbles that that. Can you tell us exactly what you are doing...
Example table:
A B C (size)
Me: 25 30 15%
Him: 30 22 11%
Her: 12 30 20%
I am trying to make a bubble chart where the Y axis is A, the X axis is B, and the size of the bubble is C. There should be only 3 bubbles. I keep ending up with six (with the labels being only "Me" and "Her"). My goal is to have three bubbles, one representing each person. Clearly I am doing something wrong. Can you help explain...?
Hi,
I wanted to add data labels to the bubbles. Each bubble represents a different company name. Excel allows me to add the size, legend, x axis values and y axis values. How do I add instead- Company A, B, C, D for the bubbles?
youon you have to choice every data for every company..
ex:create bubble for A company,after that click right> add data label> adjust data labels :format data labels and choose : series name.
i hop u will succeed .
[...] we create a bubble chart with 2 bubbles. 1 for the actual mustache & 1 for target [...]
If we want bubble size to be controlled by one column, but the bubble labels to be controlled by another column, how can this be achieved?
many thanks!!!!