Session 4 case studies
24
Edward Tufte “The Cognitive Style of Powerpoint”
Transcript of Session 4 case studies
Edward Tufte“The Cognitive Style of Powerpoint”
“PP convenience for the speaker can be costly to both content and audience. These costs result from the cognitive style characteristic of the standard default PP presentation: foreshortening of evidence and thought, low spatial resolution, a deeply hierarchical single-path structure as the model for organizing every type of content, breaking up narrative and data into slides and minimal fragments, rapid temporal sequencing of thin information rather than focused spatial analysis, conspicuous decoration and Phluff, a preoccupation with format not content, an attitude of commercialism that turns everything into a sales pitch.” (p. 4)
“PP convenience for the speaker can be costly to both content and audience. These costs result from the cognitive style characteristic of the standard default PP presentation: foreshortening of evidence and thought, low spatial resolution, a deeply hierarchical single-path structure as the model for organizing every type of content, breaking up narrative and data into slides and minimal fragments, rapid temporal sequencing of thin information rather than focused spatial analysis, conspicuous decoration and Phluff, a preoccupation with format not content, an attitude of commercialism that turns everything into a sales pitch.” (p. 4)
“PP convenience for the speaker can be costly to both content and audience. These costs result from the cognitive style characteristic of the standard default PP presentation: foreshortening of evidence and thought, low spatial resolution, a deeply hierarchical single-path structure as the model for organizing every type of content, breaking up narrative and data into slides and minimal fragments, rapid temporal sequencing of thin information rather than focused spatial analysis, conspicuous decoration and Phluff, a preoccupation with format not content, an attitude of commercialism that turns everything into a sales pitch.” (p. 4)
“PP convenience for the speaker can be costly to both content and audience. These costs result from the cognitive style characteristic of the standard default PP presentation: foreshortening of evidence and thought, low spatial resolution, a deeply hierarchical single-path structure as the model for organizing every type of content, breaking up narrative and data into slides and minimal fragments, rapid temporal sequencing of thin information rather than focused spatial analysis, conspicuous decoration and Phluff, a preoccupation with format not content, an attitude of commercialism that turns everything into a sales pitch.” (p. 4)
“PP convenience for the speaker can be costly to both content and audience. These costs result from the cognitive style characteristic of the standard default PP presentation: foreshortening of evidence and thought, low spatial resolution, a deeply hierarchical single-path structure as the model for organizing every type of content, breaking up narrative and data into slides and minimal fragments, rapid temporal sequencing of thin information rather than focused spatial analysis, conspicuous decoration and Phluff, a preoccupation with format not content, an attitude of commercialism that turns everything into a sales pitch.” (p. 4)
16
PowerPoint and Statistical Evidence
To investigate the performance of PP for statistical data, let us consideran important and intriguing table of cancer survival rates relative tothose without cancer for the same time period. Some 196 numbers and57 words describe survival rates and their standard errors for 24 cancers:
Estimates of relative survival rates, by cancer site12
% survival rates and their standard errors5 year 10 year 15 year 20 year
ProstateThyroidTestisMelanomasBreastHodgkin's diseaseCorpus uteri, uterusUrinary, bladderCervix, uteriLarynxRectumKidney, renal pelvisColonNon-Hodgkin'sOral cavity, pharynxOvaryLeukemiaBrain, nervous systemMultiple myelomaStomachLung and bronchusEsophagusLiver, bile ductPancreas
98.896.094.789.086.485.184.382.170.568.862.661.861.757.856.755.042.532.029.523.815.014.27.54.0
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0.8
I.I
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1.7
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1.3
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I.I
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95.295.894.086.778.379.883.276.264.156.755.254.455.446.344.249.332.429.212.719.410.67.95.83.0
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87.194.091.183.571.373.880.870.362.845.851.849.853.938.337.549.929.727.67.0
19.08.17.76.32.7
1.71.6
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81.195.488.282.865.067.179.267.960.037.849.247.352.334.333.049.626.226.14.8
14.96.55.47.62.7
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Applying the PowerPoint templates for statistical graphics to this nicestraightforward table yields the analytical disasters on the facing page."Sweet songs never last too long on broken radios," wrote John Prine.These PP default-designs cause the data to explode into 6 separatechaotic slides, consuming 2.9 times the area of the table. Everything iswrong with these smarmy, incoherent graphs: uncomparative, thindata-density, chartjunk, encoded legends, meaningless color, logotypebranding, indifferent to content and evidence. Chartjunk is a clearsign of statistical stupidity; use these designs in your presentation, andyour audience will quickly and correctly conclude that you don'tknow much about data and evidence.13 Poking a finger into the eye ofthought, these data graphics would turn into a nasty travesty if used for
12 Redesigned table based on HermannBrenner, "Long-term survival ratesof cancer patients achieved by the endof the 2Oth century: a period analysis,"The Lancet, 360 (October 12, 2002), 1131-1135. Brenner recalculates survival ratesfrom data collected by the U.S. NationalCancer Institute, 1973-1998, from theSurveillance, Epidemiology, and EndResults Program.
13 PP-style chartjunk occasionally shows upin graphics of evidence in scientific journals.Below, the clutter half-conceals thin datawith some vibrating pyramids framed by anunintentional Necker illusion, as the 2 backplanes optically flip to the front:
For such small data sets, usually a simpletable will show the data more effectivelythan a graph, let alone a chartjunk graph.Source of graph: N.T.Kouchoukos, et al.,"Replacement of the Aortic Root witha Pulmonary Autograft in Children andYoung Adults with Aortic-Valve Disease,"New England Journal of Medicine, 330(January 6,1994), p. 4. On chartjunk, seeEdward R. Tufte, The Visual Display ofQuantitative Information (1983, 2001),chapter 5.
C O G N I T I V E STYLE OF P O W E R P O I N T 17
a serious purpose, such as cancer patients seeking to assess their survivalchances. To deal with a product that messes up data with such systematicintensity must require an enormous insulation from statistical integrityand statistical reasoning by Microsoft PP executives and programmers,PP textbook writers, and presenters of such chartjunk.
i8
The best way to show the cancer data is the original table with its goodcomparative structure and reporting of standard errors. And PP defaultgraphics are not the way to see the data. Our table-graphic, however,does give something of a visual idea of time-gradients for survival foreach cancer. Like the original table, every visual element in the graphicshows data. Slideware displays, in contrast, usually devote a majority oftheir space to things other than data.16
PowerPoint and Statistical Evidence
To investigate the performance of PP for statistical data, let us consideran important and intriguing table of cancer survival rates relative tothose without cancer for the same time period. Some 196 numbers and57 words describe survival rates and their standard errors for 24 cancers:
Estimates of relative survival rates, by cancer site12
% survival rates and their standard errors5 year 10 year 15 year 20 year
ProstateThyroidTestisMelanomasBreastHodgkin's diseaseCorpus uteri, uterusUrinary, bladderCervix, uteriLarynxRectumKidney, renal pelvisColonNon-Hodgkin'sOral cavity, pharynxOvaryLeukemiaBrain, nervous systemMultiple myelomaStomachLung and bronchusEsophagusLiver, bile ductPancreas
98.896.094.789.086.485.184.382.170.568.862.661.861.757.856.755.042.532.029.523.815.014.27.54.0
0.4
0.8
I.I
0.8
0.4
1.7
1.0
1.0
1.6
2.1
1.2
1.3
0.8
1.0
1.3
1.3
1.2
1.4
1.6
1.3
0.4
1.4
I.I
0.5
95.295.894.086.778.379.883.276.264.156.755.254.455.446.344.249.332.429.212.719.410.67.95.83.0
0.9
1.2
1.3
I.I
0.6
2.0
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1.6
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87.194.091.183.571.373.880.870.362.845.851.849.853.938.337.549.929.727.67.0
19.08.17.76.32.7
1.71.6
1.8
1.5
0.7
2.4
1.7
1.9
2.1
2.8
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81.195.488.282.865.067.179.267.960.037.849.247.352.334.333.049.626.226.14.8
14.96.55.47.62.7
3.0
2.1
2.3
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2.0
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2.4
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2.4
1.7
1.9
1.5
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2.0
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Applying the PowerPoint templates for statistical graphics to this nicestraightforward table yields the analytical disasters on the facing page."Sweet songs never last too long on broken radios," wrote John Prine.These PP default-designs cause the data to explode into 6 separatechaotic slides, consuming 2.9 times the area of the table. Everything iswrong with these smarmy, incoherent graphs: uncomparative, thindata-density, chartjunk, encoded legends, meaningless color, logotypebranding, indifferent to content and evidence. Chartjunk is a clearsign of statistical stupidity; use these designs in your presentation, andyour audience will quickly and correctly conclude that you don'tknow much about data and evidence.13 Poking a finger into the eye ofthought, these data graphics would turn into a nasty travesty if used for
12 Redesigned table based on HermannBrenner, "Long-term survival ratesof cancer patients achieved by the endof the 2Oth century: a period analysis,"The Lancet, 360 (October 12, 2002), 1131-1135. Brenner recalculates survival ratesfrom data collected by the U.S. NationalCancer Institute, 1973-1998, from theSurveillance, Epidemiology, and EndResults Program.
13 PP-style chartjunk occasionally shows upin graphics of evidence in scientific journals.Below, the clutter half-conceals thin datawith some vibrating pyramids framed by anunintentional Necker illusion, as the 2 backplanes optically flip to the front:
For such small data sets, usually a simpletable will show the data more effectivelythan a graph, let alone a chartjunk graph.Source of graph: N.T.Kouchoukos, et al.,"Replacement of the Aortic Root witha Pulmonary Autograft in Children andYoung Adults with Aortic-Valve Disease,"New England Journal of Medicine, 330(January 6,1994), p. 4. On chartjunk, seeEdward R. Tufte, The Visual Display ofQuantitative Information (1983, 2001),chapter 5.
“PP convenience for the speaker can be costly to both content and audience. These costs result from the cognitive style characteristic of the standard default PP presentation: foreshortening of evidence and thought, low spatial resolution, a deeply hierarchical single-path structure as the model for organizing every type of content, breaking up narrative and data into slides and minimal fragments, rapid temporal sequencing of thin information rather than focused spatial analysis, conspicuous decoration and Phluff, a preoccupation with format not content, an attitude of commercialism that turns everything into a sales pitch.” (p. 4)
“PP convenience for the speaker can be costly to both content and audience. These costs result from the cognitive style characteristic of the standard default PP presentation: foreshortening of evidence and thought, low spatial resolution, a deeply hierarchical single-path structure as the model for organizing every type of content, breaking up narrative and data into slides and minimal fragments, rapid temporal sequencing of thin information rather than focused spatial analysis, conspicuous decoration and Phluff, a preoccupation with format not content, an attitude of commercialism that turns everything into a sales pitch.” (p. 4)
“PP convenience for the speaker can be costly to both content and audience. These costs result from the cognitive style characteristic of the standard default PP presentation: foreshortening of evidence and thought, low spatial resolution, a deeply hierarchical single-path structure as the model for organizing every type of content, breaking up narrative and data into slides and minimal fragments, rapid temporal sequencing of thin information rather than focused spatial analysis, conspicuous decoration and Phluff, a preoccupation with format not content, an attitude of commercialism that turns everything into a sales pitch.” (p. 4)
“PP convenience for the speaker can be costly to both content and audience. These costs result from the cognitive style characteristic of the standard default PP presentation: foreshortening of evidence and thought, low spatial resolution, a deeply hierarchical single-path structure as the model for organizing every type of content, breaking up narrative and data into slides and minimal fragments, rapid temporal sequencing of thin information rather than focused spatial analysis, conspicuous decoration and Phluff, a preoccupation with format not content, an attitude of commercialism that turns everything into a sales pitch.” (p. 4)
Chartjunk
Escaping Flatland
Small Multiples
Color and Information
Layering and Separation
Layering and Separation
Micro/Macro Readings
Micro/Macro Readings
Narratives of Space and Time
Narratives of Space and Time
Narratives of Space and Time
