The other day while doing aimless roaming on the dotcom alley, I have seen some cool optical illusions. There are so many valuable lessons optical illusions can teach us – chart makers. Don’t believe me? Read on…
We cant measure sizes either
Much has been said about our inability to measure angles. That is why most of the charting gurus recommend you to not use pie charts. But what about sizes? Well, it seems we are bad at measuring them too. Look at this illusion.
Both the orange circles are of same size. As you can see, they don’t look so. I call this a bubble chart illusion.
What can this illusion teach us?
- Use data labels
- When you make a big chart, the neighbors of a data element determine how they are perceived. Avoid this illusion by adjusting axis, rearranging data or using color.
Colors are what we think they are
We talk alot about colors in charting. But when it comes to interpreting colors, our mind is very subjective. Look at this color illusion.
Can you believe both cells A and B are of the same color?
What can this illusion teach us?
- Use fewer colors when possible. Better still use one color.
- When you need to use multiple colors, make them distinct. If you use shades of same color, make sure they are not poorly juxtaposed.
Too much data can create un-necessary patterns
Look at this optical illusion that looks like a stacked bar chart. See how the lines don’t seem parallel.
I am sure some of you would have seen a stacked bar with enough data that looks closely like the above illusion.
What can this illusion teach us?
- If you are plotting too much data on a chart, make sure the chart is readable.
- Dont place chart elements (bars in this case) close to each other, don’t separate them too much either.
Gray color messes with our gray matter
There are just so many optical illusions involving gray color that I don’t know where to begin. See this for eg.
Because of its neither here nor there nature, gray color can easily mess with our mind (and eyes). One reason why excel 2003 and earlier charts looked so ugly is because of the gray color. They had that as default background.
What can this illusion teach us?
- Do not leave your chart’s underwear on – In other words, remove that default gray background from your charts.
- Avoid using close variations of gray when you plot multiple series of data.
No matter what your chart says, your audience will see what they want
You might think your chart proves pattern A. But your audience only see the pattern B. For eg. look at this illusion:
Some people instantly see a flower vase. Others see 2 faces. And this could be true for your charts.
What can this illusion teach us?
- Don’t leave the messages for interpretation. Spell them out if you can.
We over estimate our memory power
Our mind is notoriously forgetful and unlearns things so fast. Don’t trust me? Well, see this animated illusion.
Both yellow lines are of same length. But the moment the guiding lines are removed our mind tends to think first line is smaller than the next one. Add the guiding lines again and our mind quickly learns the fact that they are of same length. Remove it and it is as if we never learned the fact. In this great TED talk, the speaker Dan Ariely talks about the same and asks whether our mind is in complete control of the decisions we make.
What can this illusion teach us?
- Next time you set out to make that 50 slide presentation, remember this: “we are poor at remembering things”
- Use data labels, keep things simple and together if you can.
No one talks about a chart, but everyone talks about an illusion
Well, what can I say. I look at at least a dozen charts everyday. And yet, here I am, talking about optical illusions. That is true for most of us. We like magic, we like wonderful things and want to talk about them. We have seen one too many charts that they don’t excite us anymore. Show me an optical illusion and I am ready to stare at the black dot for 30 seconds. Show me a pie chart and I am yawning already.
What can this teach us?
- Whenever you can, tell a great story.
- Connect with your audience in unusual and exciting ways.
- Break some rules and don’t be shy to add a spark.
Additional charting resources to help you make magic:
- Better excel chart templates – Create great looking charts with these templates
- Vizooalization – What your neighborhood zoo can teach about visualization
- Charting Principles – Simple yet very effective rules to make great charts
13 Responses to “Gantt Box Chart Tutorial & Template – Download and Try today”
Hi Chandoo
As one of your students I have followed your detailed example through with great success. However, Excel is acting in an unexpected way and I wonder if you could take a look?
http://cid-95d070c79aef808e.office.live.com/self.aspx/.Public/Gantt%20Box%20Chart.xlsm
On my version, I have to type 40239 (Which equates to 2 Mar 2010) to get the chart to display 31 May 2010 (which should be 40329)!!??
Have I done something wrong or is Excel acting up?
Thx
Oli
PS Your example file in 2007 displays correctly.
Hi,
I like this idea a lot, but I agree the name is a little drab.
As an American I may just be seeing things, but to me the combination of lines and bars on your chart looks like a bunch of cricket bats.
Maybe you could work that into a catchier name. 🙂
Cheers!
Here is some code I use to keep the axis synched.
It may be useful to some of your readers
It is based on a comment I saw on Daily Dose of Excel.
Function SynchGanttAxis(Cname, lower, upper)
'Sets the X min and X max for Category axis
Application.Volatile
On Error Resume Next
'
'Top Horizontal Axis
With ActiveSheet.Shapes(Cname).Chart.Axes(xlCategory, 1)
.MinimumScale = lower
.MaximumScale = upper
End With
'Bottom Horizontal Axis
With ActiveSheet.Shapes(Cname).Chart.Axes(xlValue, 2)
.MinimumScale = lower
.MaximumScale = upper
End With
End Function
Function SynchVerticalAxis(Cname, lower, upper)
Application.Volatile
On Error Resume Next
' Excel 2007 only
'Right hand vertical axis
With ActiveSheet.Shapes(Cname).Chart.Axes(xlValue, 1)
.MinimumScale = 0
.MaximumScale = upper
End With
End Function
@Oli.. Can you check your file again.. I see 40329...
@Dave: Even I saw things.. the bars actually looked like lollipops. How about calling this lollipop chart - now that would be yummy and goes along the tradition of naming charts after eatables (bar, pie, donut...)
@Bob: Superb stuff... thanks for sharing 🙂
Hi Chandoo
This looks really good and I think it can also be applied to show project phases / milestones.
Question: Thinking further could this be amended to display a project lifecycle (Idea through to Implementation say 7 phases) on one bar / row? Just imagine 20 projects within a programme all on one chart one bar each showing their respective lifecycle stages i.e. on one page.
Idea: As the Gantt Box Chart this is quite intensive to set up re formatting etc how about the added extra of once you have completed this to "Save as template" i.e. saves the formatting and layout of the chart as a template so you can apply to future charts. Simple to do and will save the time formatting etc again and again and again.
Therefore tip: Click on your chart demo and then click on Save As template icon (2007) - edit file name and click on save. Ready to use / apply via Templates in Change Chart Type window.
Thanks and be very interested if the lifecycle question can be resolved
Mike
How embarrassing.
I was obviously suffering from numerical dyslexia. I was one of those days.
@Mike H: You can easily make this chart to work like a generic project lifecycle plan chart. All you have to do is,
1. in a separate sheet define the steps of lifecycle and various dates in a table (with 5 columns for each of the projects you have).
2. now use a control cell to input the project name you want to show in the chart
3. based on the input, use OFFSET Formulas to get the correct data
4. Rest is same as the tutorial above
For more info on the dynamic charting visit http://chandoo.org/wp/tag/dynamic-charts/ and http://chandoo.org/wp?s=OFFSET
Your solution is really smart but in the en Excel isn't meant to do stuff like this. I, as a former PM, always thought is was frustrating that you had to do stuff like this for something simple like a Gantt chart. So I built Tom's Planner. And would like to plug it here. I think it really solves the problem you are trying to solve in the most efficient way. Check out http://www.tomsplanner.com for a free account or play around with the demo.
Hi there,
Chandoo - this is really a very nice and helpfull chart - I adopted it, so I can report a forecast or the delay of a certain task (coming from my role as an auditor for projects).
One topic I´m currently struggeling with: I do have a project lasting for lets say 12 month. For a management reporting, I want to have kind of snapshot, lets say one month back and 2 month in the future. I tried with the offset formula, but failed. Any idea?
Thx
Lopi
[...] Ein viel geliebter Klassiker ist die Erstellung von GANTT-Diagrammen mit Excel. Wir hatten das Thema wiederholt schon hier. Chandoo.org hat sich mal wieder mit einer neuen Variante hervorgetan: Das GANTT-Box-Chart. [...]
[...] [...]
Hi Chandoo - fantastic xls. One thing I can't figure out how to do is adjust the alignment of the vertical axis. I would like to left align so that I could indent to represent sub tasks. Can that be done? Or is there a better way?
I've been trying to work out if there's a way to show weekends on the graph. The closest thing I've got is to add them on a secondary axis, but then I haven't been able to keep both axis lined up together! Any ideas?
Following on from this - is it possible to show things like holidays?