Last week I have reviewed Google’s flu trends chart and told you why it is an awesome chart. This week, I am going to show you how such a chart can be constructed in Excel.
First let me show you what I am able to do in Excel:

(compare this with actual chart on Google)
How I made the flu-trends chart in excel?
- Data, Data, Data: Data plays an important role in complex charts like these. The source data is thankfully available for download from Google. Flu incidence data is available by week (Sunday to Saturday) for every week since 28th Sep, 2003. For each week the data if given for all regions in various columns. But I was not able to use the data “as-is” to construct this chart. I had to massage and rearrange it a bit.
- The main issues is how flu season is classified (it starts on July and ends in June) and how the data is (we got weekly flu incident data, starting from Sunday to Saturday). The main issue here is each year, the weeks start on different dates. For eg. first Sunday in 2010 was on 3rd Jan where as in 2009 it was on 4th Jan. I tried using WEEKNUM() formula (examples), but it didn’t work well with the flu season (Jul to Jun). So I did some basic date math and ended up mapping weeks uniformly across years.
- The next issue is taking one big table of data with dates in rows and regions in columns and transform it to weeks in rows, years and columns and actual flu data for the selected region in the cells.
- Then I set up 2 cells, one where user would specify “region” and other where a comparison “year” can be selected. I have used data validation to control the valid inputs.
- I used the MATCH, INDEX formulas to fetch corresponding weekly values for all years for selected region. Thanks to MATCH, INDEX and HLOOKUP formulas, this is not such a big task either. And if the optional comparison year is specified, we repeat that years values in another column. Otherwise that column is NA().
- Using these columns, I made a line chart. Then I cleaned up the chart and formatted the 2009-2010 series in thick blue and rest all in thin light blues. The optional comparison series was colored in red (for contrast). [related: line chart examples]
- The only remaining piece is to show the heat map of flu intensities below the chart. For this I have used the very useful 3 color scale conditional formatting setting in Excel 2007. (of course, I had to setup some extra calculations so that the intensities are normalized across the region / years and change when user selects a new region, but you already guessed it.)

- I choose to drop the colorful legend as it adds little value.
- The rest is some formatting and presentation.
What I learned from this experience?
- When I looked at Google’s chart, I doubted if it can be created in Excel. But I was wrong. It can be done in excel, and it takes no more than 2 hours.
- Data and structure of it play extremely important role in any visualization.We should understand the data and know how to arrange / transform / massage it, to make better charts.
- Date formulas are a flu in the nose.
- Excel 2007 conditional formatting is just awesome. [more examples]
- INDEX, MATCH, LOOKUP formulas are very powerful. I *respect* them. [here is a tutorial]
Download flu trends chart and play with it
Download the file (Excel 2007 only). The file is locked, but there is no password. Play with it and tell me if you like it.
Do you like this chart?
Have you done something similar in Excel? What was your experience like? Do you like this chart? How would you improve / change it?
More visualizations using Excel:
Olympic Medals by Country | Survey Results Dashboard | Test Cricket Statistics | Dynamic Charts
PS: After a looong time this post had many “I”s
PPS: Have a good weekend.

















30 Responses to “Great News: Chandoo becomes MVP”
Congratulations! It's well deserved. 🙂
This is amazing. Hearty congratulations and a rocking new year ahead!!!
Congrats! I have learnt alot from your site... and the most important is learning how to achieve the most with the simplest concepts.
Thanks for the excel calendar. Is it possible to get a simple big fonted calendar printable on an A4 size paper without any distracive notes or visuals? BTW, I have already signed up for your newsletter. With warm regards and
Gratefully yours
50+ year old CHarish.
Hey Chandoo,
Great to hear that. Congratulations! The best new year gift, I would say. Keep it up, u've been doing extraordinary work for the excel users community.
Regards,
Pankaj Verma
Congrats dude... fantastic news!
congratulations! your site is great, this is well deserved
Rich
I recently found your site, I visit many. The tips that you provide are in the top 1% of all the sites I visit. Keep on Excelling.
Arnold
South Africa
Congratulations, Chandoo! That's a great way to start the year and make the PHD even better.
Congratulations, Chandoo.
Your site is one of most useful on the net. Happy new year and lot of ideas you will present for us.
Congrats.
Just read your name in an email from Abhishek. Well deserved.
Congratulations, and Happy New Year.
Greetings from Rio de Janeiro my friend! You trully deserve it!
Nive way to start 2009! Keep up the good work!
FC
That was quite forseeable , so you have now really got your PhD in excel.
Anyways Chandoo you have made excel a real Fun doo
I will like you to write some more on INDEX and MATCH function in near future.
@Hey Chandoo ! Congrates....
Ab to treat mangta hai !
Well deserved Chandoo!!
Congrat's!! Very well deserved 🙂
i always browsed mr.excel and used to see MVP writtne below names of people who used to solve queries in excel forum there......i just used to admire as to what they have special in them that they are MVP......
but now i got my answer...............u deserve it man..........
@All: thanks everyone 🙂
Congratulations Chandoo, nice job!
Chandoo,
A well deserved recognition and a good start to the New Year. Continue your good work.
Subbu
Many Congratulations.
You deserve a Ph.D. 🙂
congrats.....
Congrats dude. Rock on!
[...] charting community in 2007 and has been growing strongly ever since. In year 2009, I have received the MVP award from Microsoft. Just few days back I have become a dad [...]
Respected sir,
I am impressed!.... Good job done.. Keep it up...
Sir, How to be a MVP certified person. What level of knowledge is required for it? send me links if possible.
Please reply...
Regards,
Dipak Khalasi.
Dipak -
The first thing you need to cultivate is the ability to search the web effectively. You could start by Googling "Microsoft MVP".
[...] boy and girl which has been made hectic and incredibly fun ever since to their life.He has been awarded MVP status in 2009 by Microsoft(and renewed in 2010,2011 & 2012).His MVP profile is here.If you want to contact him direct then [...]
Congrats Chandoo!!
[…] Chandoo becomes MVP […]