New Year’s Resolution: Tufte and the iPhone
By Chris Gemignani
January 24, 2008
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sparklines
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Edward Tufte has produced a illuminating video tour of the user interface of the iPhone. The video illustrates Tufte’s struggles to come to grips with the difference between dynamic screen resolution and the resolution of printed paper. Tufte is prone to grandiose pronouncements, like this one:
All history of improvements in human communication is written in terms of improvements in resolution: to produce, for viewers of evidence, more bits per unit time, and more bits per unit area. Slideware is contrary to that history. Trading in reductions in resolution for user convenience or for pitching may be useful in mass market products or in commercial art, but not for technical communications. The solution is not to rescue slideware design; the solution is to use a different, better, and content-driven presentation method. On this solution, see our thread PowerPoint Does Rocket Science—and Better Techniques for Technical Reports — Tufte Nov 10 2006
Somehow, I don’t think the importance of the Gutenberg Bible related to it showing “more bits per unit area.” Quick, count the “bits per unit area.”


It didn’t take bits per unit area to revolutionize communication in the past and it won’t in the future either. The iPhone is a tremendously engaging information device and points the way forward for information displays. Here’s what the iPhone does well:
Maximize screen real estate: Controls are only visible when needed, fading away gently when you are concentrating on content. Tufte furiously neologizes, calling this “computer information debris.” Control junk is more apt, more terse, more Tuftian.
Direct manipulation: As Tufte says: information is the interface. Filtering and choosing should take place in the context of direct manipulation. A good essay on the possibilities of direct manipulation can be found here.
Fun: Above all, information can be fun and engaging to navigate. Tufte condemns Apple’s stock ticker for having “cartoony” and PowerPoint-like displays and offers an improved version (with 5 digits of precision). Apple’s cheery display offers a more entertaining, usable interface for day-to-day usage.
With our empathy for the day-to-day troubles of the business person seeking insight in data, it’s frustrating listening to Tufte. He is clearly an academic, with academic interests and academic timeframes. As much as his work is respected and inspirational within business circles, he makes little effort to enable his message to be implemented.
Good Tufte: Clutter and overload are not an attribute of information, they are failures of design. If the information is in chaos, don’t start throwing out information, instead fix the design.
Bad Tufte: “…the conclusion of sparkline analysis in Beautiful Evidence, where the idea is to make our data graphics at least operate at the resolution of good typography (say 2400 dpi).” http://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msgid=0002NC&topicid=1 *Ed: At least 2400 dpi? Orly?
Mostly right Tufte: “Thus the iPhone got it mostly right.”
Mostly wrong Tufte: “Adobe Illustrator is a big serious program that can do almost anything on the visual field (other than Photoshop an image). Most of my sparkline work was done in Illustrator. Fortunately all graphic designers and graphic design students have the program and know how to use it, so find a colleague who knows about graphic design.” http://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msgid=0000Jr&topicid=1&topic=Ask%20E%2eT%2e
It is heartening to see Tufte engage and connect his mental frameworks to our modern, screen-oriented, graphics-accelerated, not graphics-designed world. But the future of information design and interaction belongs to the iPhone, not the printed page.
Excel 2007 and the Lie Factor
By Chris Gemignani
June 7, 2007
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tufte
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“The representation of numbers, as physically measured on the surface of the graphic itself, should be directly proportional to the quantities represented.”
Edward Tufte calls violation of this principle the “Lie Factor”. The implementation of in-cell data bars in Microsoft Excel 2007 is a big offender.
Almost a year ago, I was surprised to discover that the Microsoft Excel 2007 development team didn’t understand what zero means. Their implementation of in-cell data bars showed a bar in a cell, even if the cell had a zero or very low value.

That was in the Excel 2007 Beta. Things haven’t improved in the current version of Excel 2007. The default setting for data bars in Excel 2007 is to scale to bars so that the smallest bar is based on the smallest value in the selected range and the largest bar is based on the largest value. It still appears that the smallest bar will be no smaller than five or ten percent of the width of the cell. Here’s a sample:

So, if you select a range that has values between 600 and 700, the 600 would have a little bitty bar and the 700 would have a full-width bar. Based on the bars, it would look like the 700 is ten to twenty times larger than 600. Outside of Redmond, this is generally regarded as untrue.
What’s more, if you create two sets of data bars side by side, each group of data bars scales itself independently even though they look the same. Take a look at this screenshot:

Notice the top seven cells have data bars that have one set of scaling and the bottom data bars have a different scaling. However, they look identical, and users should generally expect these bars to have the same scale.
Here are the rules:
- Defaults matter! It doesn’t matter that you can do data bars correctly in Excel. The default should be to do it right and it should be hard to do it wrong.
- The “right way” to make data bars is to make the length of the data bar directly proportional to the value in the cell. If one cell has a value twice another it should have a bar that is twice as long.
- Remove the default gradient shading. The gradient makes it hard to tell where the bar ends, obscuring what you’re trying to show.
- Continuous cells with data bars should all use the same scale. Use different colors to indicate ranges that have different scales.
Excel 2007 supports at least twenty-five different combinations of ways of specifying the length of the data bar.

Exactly one of those ways is correct. Base the shortest bar on the number 0. Base the longest bar on the highest value. Turn off the gradient. If you want to see bars based off percentile or some custom formula, then be explicit. Create a new column, create your formula, create bars on that column.
Please, guys, this isn’t rocket science. This is plain common sense. You would not ship Microsoft Word with a glaring bug in the way text renders. You would not ship Excel with a broken statistical function that people use everyday. Delivering deceitful-by-design infographics betrays your central role in democratizing the analysis of data. Until you fix this, in-cell ASCII art still remains the best way to explore data visually.
A disclosure: We do not currently use Excel 2007 at Juice Analytics. This is not due to a high-minded sense of moral outrage but is merely a reflection of our clients' environments.
9 comments | Show all comments only the last 5 are shown
James L. said:
“The representation of numbers, as physically measured on the surface of the graphic itself, should be directly proportional to the quantities represented.”
Although unrelated to the article, I was wondering what your take would be on the use of logarithmic scaling? This violates "direct proportionality", but is quite common in scientific/engineering fields (I myself used it the other day).
Chris Gemignani said:
My initial thought is that logarithmic scaling doesn't work in the context of in-cell graphing. Log scaling would be really hard to use without an axis and is probably best when you're comparing time-series trends in a line chart. Thanks.
Will Oswald said:
"You would not ship Excel with a broken statistical function"... erm, unless you include the LINEST function that up until Excel 2003 did not adjust for collinearity in multiple regressions, a fundamental problem
Chris Gemignani said:
You noticed I qualified my statement with "that people use everyday". I have heard about this problem and others in with Excel's statistical functions. These problems should have been fixed as soon as they were reported.
R Varley said:
Hi, I'm trying to write an evaluation document on Excel 2007; everyone seems to think it's rubbish for statistics, but no-one says what's wrong. I've been trawling the internet for days, and turned up nothing beyond "Everyone knows it's broken". Can you give me any pointers?
Thanks.
Patrick O'Beirne said:
1st Oct 2007:
Data Bars – Feedback Please
Today’s author: Scott Ruble, the program manager who leads the charting and visualization efforts in Excel. Scott is looking for some feedback on potential changes to data bar behaviour.
http://blogs.msdn.com/excel/archive/2007/10/01/data-bars-feedback-please.aspx
Chris Gemignani said:
Patrick, I commented on the Excel databars post. I'm astonished that these questions keep coming up. The solution is simple: "You need to start with the absolute principle that the bars you show _must_ be proportional to the numbers they represent."
Greg said:
Is there a way to turn off the gradient fill in the data bars?
Matt Craig said:
I have used another way to represent data bars "in cells", but it is "clunky". I create a bar chart, turn off every interface element except for the bars, make the bars slightly transparent (if I still want to see the numbers), and then put it on top of the cells.
It works, but it's "clunky" - the scaling and placement is finicky. It is pretty nice when it's done though, as you can apply appropriate rules to the display of the graph. (e.g. 0 = 0 length), and it gets rid of the annoying gradient (the reason I did it in the first place)
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And Ye Shall Know Me By What I Do Not Do
By Chris Gemignani
August 2, 2006
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Jeremiah McNichols writes about one of our posts on sparklines with a critical eye on the limitations of this idea.
None of this is intended to suggest that Sparklines are not useful; indeed, their overextension may be the natural result of the obvious, instinctual, and dramatic utility that accompanies truly innovative ideas. But I do believe that when the dust settles from this discovery, they will be implemented with greater care.
This is a great point tactfully raised. Any approach, technique, or technology is good on certain problem domains and bad on others. Commercial vendors and sellers of BI tools would like you to believe their product works great in all cases all the time.

Wouldn't it be great if vendors spent as much time talking about where their product should not be used as where it should be used? I can see the marketing now: "Only a COMPLETE IDIOT would use Microstrategy to solve X", "If you want to use Business Objects to support Y, it would be quicker to just throw your money away because it isn't going to work."
1 comment
Henk said:
Overextension is a probable sign of an underlying latent need. In other words: a great business opportunity. But beware: it also attracts adventurerers looking for the quick bucks, selling you anything, not hindered by their lack of expertise. I agree, Chris, that the true BI master posesses \'know why\' (and \'why not\', for that matter!). Know \'how\' requires skills, but applied to the wrong problem these skills are as useless as an ashtray on a motorbike.
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A Missing Link in Business Analytics (Part 2)
By Zach Gemignani
May 24, 2006
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analytics
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In a previous post, we described how NFL coaches and players use film study as their approach to analysis. We argue that "slicing and dicing" statistics doesn’t help much when deciding on a game plan. Business intelligence tools can explain the size of the problem (how good is the opponent?) and trends (what are their preferred offensive weapons?). These same tools do not, however, provide real perspective on customer behaviors or insights that give your organization data-driven direction.
The question remains: How do we bring the value of film study to business intelligence? The solution we've used is inspired in equal parts by Edward Tufte and Malcolm Gladwell.
Tufte is a well-known expert in presentation of informational graphics. Among numerous concepts, he popularized the idea of sparklines: "data-intense, design-simple, word-sized graphics.” Here is a sparkline showing deficit spending from 1983 to 2003:
What if there was a way to create data-intensive pictures that represent customer behaviors? They could draw on customer usage of a product, marketing touch-points, service calls, and any number of other relevant interactions. The goal: create a simple representation that quickly shows customer behaviors that matter to your business. Here are a few examples from our work:

These pictures are intriguing, but can they be useful? In his book Blink, Malcolm Gladwell introduces the idea of thin slicing: "the act of relegating the decision-making process to the adaptive unconscious by focusing on a small set of pertinent key variables, as opposed to consciously considering the situations as wholes over much longer periods of time." He explains how people become experts at quickly evaluating the relevant data and arrive at a rapid understanding of a situation.
We want to give business people a sense of their customers in a blink of an eye. To do so, customer sparklines need to be intuitive and easy to learn. Success is the ability to show these pictures to anyone in the organization—from senior executives to front-line customer service reps—and have them grasp what they are seeing with just a few minutes of explanation.
A Missing Link in Business Analytics (Part 1)
By Zach Gemignani
May 10, 2006
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sparklines
Insightful analysis of data is important whether you are in business or sports. However, the approaches used in these arenas couldn't be more different.
Take the NFL, for example. Coaches and players spend hours analyzing film to identify the strengths and weaknesses of opposing teams. As much as any professional league, game planning can make the difference in setting-up a team for success. For players, film study is the mental foundation that lets instinct take over on the field. Given the importance of this raw data analysis, it is worth tapping into my ESPN Sunday morning education (thank you, EA Sports NFL Matchup) to considering the techniques involved:
Get granular: Examine the raw data like where players are positioned, who gets the ball from different formations, what plays are called at different field positions, and even what techniques are used by individual players.
Use your eyes: Rely on your brain's powerful ability to recognize patterns (or "tendencies" in football-speak). Record these patterns by player, by formation, by down and distance.
Create a common context: Given the volume of data, it is important to focus on the differences while holding everything else constant. For the Tampa Buccaneers (and presumably most NFL teams): "every game and practice session - every step, block, throw, kick, zig and zag - is captured on film from two bird's-eye views: sideline and end zone. The tapes then are intercut so each play can be seen from both angles."
Group common patterns; highlight anomalies: The building blocks of analysis become the common patterns. How frequently does the team behave in a certain way? Does this occur more often in the red zone? Also, after watching enough film, unusual actions on the field pop-out quickly.
Bottom-up strategy: Finally, use this deep understanding of all the opposing team, players, and patterns as the foundation for the game plan.
This type of approach is a far cry from the types of drill-down analyses most common in businesses. Imagine if a NFL team depended on business-type statistics and OLAP reporting. How valuable would it be to look at:
- Average yards per carry,
- Trends in passing versus rushing yards,
- Distribution of touches by player,
- Individual player statistics?
This type of "slicing and dicing" of the statistics can show the size of the problem (how good is the opponent?) and trends (what are their preferred offensive weapons?), but it wouldn't get a coach much closer to figuring out what to do about it.
And that typifies the stuck state of analytics in business today. Business intelligence tools are good at reporting and showing trends. These same tools are not good at understanding customer behaviors or complex processes--the types of understanding that provides a solid foundation for marketing, operations, and even corporate strategy. The tools don't help with the one question that matters whether you are in business or in sports: what should I do based on the evidence?
In Part 2, we'd like to share one idea of how to get deeper into the data so you can get smarter: an approach we call "customer sparklines."
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This is an Intervention! A Rehabilitation Program for Business Intelligence said:
[...] Who can help? At Juice, we believe that there are a lot of hidden insights in the detail, if you can find compelling and visual mechanisms for presenting the data. Our approach is called Customer Flashcards; use the idea, find a better name. [...]
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3 comments
ross said:
Nice post, thanks for making it, I found in interesting and I think it's good that people are prepared to quest Tufte, who seems to have rightly or wrongly some God like stature.
For my part, I have used TyTN's series since mark 1 and these, running windows mobile, have had all of the features (more or less) of the iPhone for some time. Compromise in the key with small devices. - Untill we get screen that can project into air! :-)
Cheers
Ross
mahalie said:
It's always folly to never question anything someone says just because you have a lot of respect for their ideas generally. Yet I see many bloggers flame well-respected experts...probably as traffic bait. So great to hear a voice of reason. Thanks!
darrell said:
"To clarify add Detail" - as an example, Tufte adds a satellite weather pattern to augment a weather forecast of X degrees and Partly Cloudy. How does that clarify? You need expertise to interpret it, and it didn't offer analysis / interpretation just raw data (satellite view).
I understand his point if you're presenting to a panel of experts. But the iPhone is sold to consumers, not weather forecasters.
Few of us are weather forecasting expertise (beyond idle speculation). Using the satellite video, a non-expert could probably guess, the degree of cloudy, and perhaps the direction of the wind. Other useful info like wind speeds, wind chill factor, probability of precipitation and temperature are not aided by the satellite visual.
Eye candy; yes. Useful; only to a limited expert audience, and only with additional information not displayed.
"To Clarify; first consider the audience, then add relevant detail."
said:
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