Tag Archives: bar chart

#MRA_FOC #MRX Effective Data Visualization by Naomi Robbins, Part #1

nbrgraphs

I was caught between a pillow and a soft place this morning with a choice between a session on social media and the other a session on charting. But, as a fan of Edward Tufte, a legendary charting specialist, I couldn’t resist attending Naomi’s data visualization session.

She began the session by testing the room lighting to see if the colours on her presentation would show correctly on the screen, something I can appreciate having  given presentations myself where a variety of colours ended up looking the same. It is something everyone should do particularly if you are presenting charts. If your labels, gridlines, or distinguishing chart features don’t show up, you might as well not do the presentation at all.

Here are just a few of my favorite points:

  • The best chart is the one where the information is detected most quickly
  • If perceiving the information is not important, then a pie chart is fine, e.g., when the chart is used as decoration
  • The way you read a chart depends on which software you use and labeling the data points does not make a bad chart ok. See the chart below to see if you can determine what the data points are. Does the line match up with the front of the bar, the back of the bar, or neither!
  • Graphs are to show relationships and trends, not exact numbers. If you need exact numbers, then use a table. Hence, bar charts do not need numbers.
  • All bar graphs should start at zero because bars reflect length which has a zero.
  • Alphabetical order is rarely the best way to order data.
  • There is no substitute for colour.
  • People know what number comes between 88 and 90 so you don’t need to label every point.
  • When we use error bars, we often use 68%. But 68% makes sense in a table for self-calculation. Doesn’t 95% make more sense in a chart?
  • Museums want to show data honestly and accurately. Corporations….. have other ideas. :)

Naomi presents in a style reflective of a professional statistics geek with tons of charts and examples and I got quite a kick of the morning session. She showed us a lot of tricks that I like to play on my colleagues such as having them guess chart values on really bad charts. She showed us a number of charts that I have never seen before and am now anxious to try. She showed many examples of bad charts turned good with just a couple minutes of work. She provided a set of notes that is probably the best set I have EVER come across. She suggested that though Edward Tufte is a charting genius, he is not the only expert in charting and she introduced us to William Cleveland, one of her favourite experts.

This slideshow highlights just a few of the huge range of charts that Naomi highlighted. You really need her commentary to see just how funny some of the charts are but I’m sure you’ll enjoy them anyways.

This slideshow requires JavaScript.

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Conversition Strategies Social Media Research: By researchers, For researchers
conversition strategies social media research by researchers for researchers

Thanksgiving for Research

[tweetmeme source=”lovestats” only_single=false]I am thankful for pie charts that are used to represent percentages out of 100 as opposed to numbers summing to 217.63.

I am thankful for bar charts that reflect quantities of categorical data not trends over time.

I am thankful for knowing whether a rating scale reflects an ordinal or interval scale.

I am thankful for 3.1415927 and chocolate.

I am thankful for loving the work I do and wanting to go to work, for I know that is a rare occurrence.

5.367 tips for presenting charts people will like

Jordens inre

Image via Wikipedia

Having just attended and presented at several conferences, and with one more on the list, I’ve seen more than my fair share of powerpoint presentations in the last few weeks. Some had some great slides, and, well, others I can’t say anything about because I couldn’t read them.

As a presenter, I know you have a ton of things to worry about. Is your topic interesting? Are YOU interesting? Can you fill up so much time and not flub it all up? It seems we leave building a readable presentation to the end of the list and then we never actually finish the list.

With that in mind, here are just a few tips that will result in your audience being more appreciative of your presentation. And they’re quick so try them out!

  1. If one line or bar represents the “right” number, colour it green. And vice versa, if one line or bar represents the “wrong” number, colour it red. People are primed to interpret green as go and red as stop so help them understand your data more easily.
  2. If you’re using a line chart, make the lines really thick, thick as in 5 to 10 points. There will be people at the back of the room because there are no seats at the front (yay!). Help them like your presentation by allowing them to see the data too.
  3. Increase the font sizes to crazy big numbers everywhere. Do you need a vertical scale? Increase that font! Need a horizontal scale? Increase that font! Make it so big and fat that it looks wrong – because it will look right from the back of the room. Font sizes should be at least 20 points but go with 30 or more if you can make it work.
  4. Make the chart as big as you possibly can. Take extraneous words off the page to give more room to the chart. If the words aren’t on the page, it will give you something to say instead of read. And people will be grateful for it.
  5. For the love of God, don’t make your chart 3D! Sure, it may be pretty but 3D in presentation style is ten times worse than 3D in paper style. There’s no way your audience can pull your slide close to their face to more accurately interpret all the extra chart junk that 3D creates. Simple is good. Simple is readable.

5.367. Do not default to the default chart. Default charts are there for people who shouldn’t be using charts in the first place. You are smarter than your software so think about your audience, your purpose, the room where you’ll be presenting and create a custom chart that will work for that specific situation.

Why 5.367? Because people are more likely to believe numbers that use decimal places. Do you believe that?

Read these too

Permissible pie charts and 1 bar chart

[tweetmeme source=”lovestats” only_single=false]Why oh why do I give pie charts such a bad rap? Because people find them so easy to make that they use them for all the wrong reasons. Here are three simple rules for making a pie chart.

  • Slices must represent percentages not counts or dates or timelines or averages.
  • Slices must always add up to 100%. Not 412. Not 73. Not 0.037. Only 100%
  • Slices representing the same number must always appear to be the same size. 3D pie charts do NOT do this.

Below are permissible forms of pie charts as well as one bar chart. Even better, these are permissible forms of 3D pie charts. If you’re unsure about whether your pie chart is failing one of the above requirements and it doesn’t fit in one of the below options, do not make a pie chart.

Read these too

  • Huh? I never pay attention to you anyways. #MRX
  • 5.367 tips for presenting charts people will like
  • Are Professional Responders the Real Enemy?
  • Why Do I Always Screen Out of Surveys
  • Thoughts and Opinions of the MR Industry – The Researcher’s Perspective
  • A Pie Chart of my Favourite bars…

    [tweetmeme source=”lovestats” only_single=false]…and a bar chart of my favourite pies.
    Inspired by the television show “How I Met Your Mother.” See? I am NOT the only chart fanatic out there!


    PieBar.PNG

    Thanks to @zebrabites for making me see the light. THIS is a pie chart of my favourite bars!
    .

    Pie Chart of Bars

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