Here is the big hairy question of the week. What is your opinion on Pie Charts?
Pie charts are one of the most used charts in the world. And for obvious reasons: they are simple to create and easy to understand.
When it comes to pie chart, I have no clear opinion. Part of me says use them, the other says avoid them. The debate about pie charts is not just internal. Last time when Seth Godin included pie charts in his 3 laws of great presentation,
The problem with bar charts is that they should either be line/area charts (when graphing a change over time, like unemployment rates) or they should be a simple pie chart (when comparing two or three items at the same scale).
there was so much furor in the data visualization blogosphere that Seth even did a follow up post comparing bars with pie charts, where he says,
The pie chart contains far less data, but the point is obvious: Trolls are where we should focus our energy.
That’s why you use it. …
I stepped on the toes of many data presentation purists yesterday, so let me reiterate my point to make it crystal clear: In a presentation … the purpose of a chart or graph is to make one point, vividly. Tell a story and move on.
Personally I think pie charts provide great utility at very little cost:
- They are very easy to create
- Very very easy to understand (provided the data has some contrast, if your numbers are like 43,44,45,46, there is little chance that anyone can understand the resulting pie chart and make out which one is large and which one is small)
But, I also think they are easy to abuse (one reason why you see way too many pie charts compared to other charts).
Here is what I think cripples a pie chart from being effective:
- Too many data points. A pie chart would probably be effective up to 4 values, anything more and you better have a strong story behind it for people to read and interpret. For eg. the pie chart shown to the right is used in Google Analytics reports. This compares browsers used by visitors of a site and even though there are probably hundreds of browsers, only 2 are prominent, so the pie still works.
Poor use of color. The purpose of color in most visualizations is to bring contrast. To separate apples from oranges. To throw light where your story lies. But most programs that are used to generate pie charts have poor (and often scary) color choices. When you use poor color combinations, the result will be drastic. But this blame is not on the person making pie charts, but on the pie chart software. See the example aside from clearlyandsimply to see what contrast means.- Making Pie charts that are difficult to compare. The purpose of pie charts is to provide comparison. So when we make a pie chart that has poor ability to compare, we are already lost. That means we should avoid all the flashy formatting, 3d pie charts, 3d donuts and layered donuts etc. Also, whenever possible, try Using data labels, using color and if nothing works, try using other types of charts for comparison. After all, we are not selling pie charts, we are selling our stories.
Ok, now the ball is in your court (or the pie is in your plate).
What do you think about pie charts?
Do you prefer them or do you consciously avoid them ?
How do you think pie charts can be put to better and greater use ?
Your turn…
Earlier on pie charts: Why no one likes your pie & what to do about it? | In cell pie charts | 22 beautiful pie chart templates for excel
12 Responses to “29 Excel Formula Tips for all Occasions [and proof that PHD readers truly rock]”
Some great contributions here.
Gotta love the Friday 13th formula 😀
Great tips from you all! Thanks a lot for sharing! bsamson, particularly you helped me on a terribly annoying task. 🙂
(BTW, Chandoo, it's not exactly "Find if a range is normally distributed" what my suggestion does. It checks if two proportions are statistically different. I probably gave you a bad explanation on twitter, but it'd be probably better if you fix it here... 🙂 )
Great compilation Chandoo
For the "Clean your text before you lookup"
=VLOOKUP(CLEAN(TRIM(E20)),F5:G18,2,0)
I would like to share a method to convert a number-stored-as-text before you lookup:
=VLOOKUP(E20+0,F5:G18,2,0)
@Peder, yeah, I loved that formula
@Aires: Sorry, I misunderstood your formula. Corrected the heading now.
@John.. that is a cool tip.
Hey Chandoo,
That p-value formula is really great for a statistics person like me.
What a p-value essentially is, is the probability that the results obtained from a statistical test aren't valid. So for example, if my p value is .05, there's a 5% probability that my results are wrong.
You can play with this if you install the Data Analysis Toolpak (which will perform some statistical tests for you AND provide the P Value.)
Let's say for example I've got two weeks of data (separated into columns) with the number of hours worked per day. I want to find out if the total number of hours I worked in week two were really all the different than week one.
Week1 Week2
10 11
12 9
9 10
7 8
5 8
Go to Data > Data Analysis > T-Test Assuming Unequal Variances > OK
In the Variable 1 Box, select the range of data for week 1.
In the Variable 2 Box, select the range of data for week 2.
Check "Labels"
In the Alpha box, select a value (in percentage terms) for how tolerant you are of error.
.05 is the general standard; that is to say I am willing to accept a 95% level of confidence that my result is accuarate.
Select a range output.
Excel calculates a number of results: Average (mean) for each week's data, etc.
You'll notice however that there are two P Values; one-tail and two-tail. (one tail tests are for > or .05), the number of hours I worked in week two is statistically equivalent to the number of hours I worked in week one.
So here’s a way you might want to use this. You put up a new entry on your blog. You think it’s the best entry ever! So you pull your webstats for this week and compare it to last week. You gather data for each week on the length of time a visitor spends on your website. The question you’re trying to prove statistically is whether there’s an average increase in the amount of time spent on your website this week as compared to last week (as a result of your fancy new blog post). You can run the same statistical test I illustrated above to find out. Incidentally, it matters very little to the stat test whether the quantity of visitors differs or not.
Anyhow, the Data Analysis toolpack doesn't perform a lot of stat tests that folks like me would like to have access to. In those cases I have to either use different software, or write some very complicated mathematical formulas. Having this p-value formula makes my life a LOT easier!
Thanks!
Eric~
Fantastic stuf..One line explanation is cool.
Thanks to all the contributors
OS
Take FirstName, MI, LastName in access (you can fix it to work in excel) capitalize first letter of each and lowercase the rest and add ". " if MI exists then same for last name:
Full Name: Format(Left([FirstName],1),">") & Format(Right([FirstName]),Len([FirstName])-1),"") & ". ","") & Format(Left([LastName],1),">") & Format(Right([LastName],Len([LastName])-1),"<")
I teach excel, access, etc etc for a living and i have my access students build this formula one step at a time from the inside out to show how formulas can be made even if it looks complicated. Yes I know I could just do IsNull([MI]) and reverse the order in the Iif() function but the point here is to nest as many functions as possible one by one (also I illustrate how it will fail without the Not() as it is)
Extract the month from a date
The easiest formula for this is =MONTH(a1)
It will return a 1 for January, 2 for February etc.
if in a column we write the value of total person for eg. 10 if we spent 1.33 paise each person then how we get total amount in next column and the result will in round form plzzzzz solve my problem sir................... thank u
@Anjali
If the value 10 is in B2 and 1.33 paise is in C2 the formula in D2 could be =B2*C2
If the values are a column of values you can copy the formula down by copy/paste or drag the small black handle at the bottom right corner of cell D2
kindly share with me new forumulas.
How to convert a figure like 870.70 into 870 but 871.70 into 880 using excel formula ? Please help.