Communicating Quantitative Information

More on diagram assignment. Dimension.Everyone dies.  Dying young[er] versus bad

breath. Car versus airplane accidents. (Immediate risk. Cumulative risk. Reported

incidences.) Homework: Continue regular postings.

Complete diagram assignment.

Diagram assignment• Read/review recent News forum

postings/messages.• Most of the Many eyes, McCandless,

Gapminder, etc. are from large data sets, often collected automatically– You may register at Many Eyes, pick a topic, upload

and use tools to get visualization, etc. for your presention

• You can do things with small or smaller data sets.– data given in postings– data in class stories– ???

Volcano

• Data / graphic from David McCandless talk.

• Compares CO2 (3 numbers)

• Comments?

Diagram assignment

• [Again] you can hand draw, make collage, add to Excel chart or graph.

• You can stick to within Excel but use Excel features to label, annotate, decorate.

• Do proofread / review.

• Be professional.

Puzzle

• At a certain school of 400, only 250 are taking math. 100 not taking math OR science. Of the students taking math, 40% are taking science.

• How many are taking science?

Fitting together puzzle

• 400 freshmen, 250 taking math

More information

• 400 freshmen, 250 taking math

• 100 taking neither math nor science… so out of the not taking math part…

Note: this part is 400-250 is 150

… out of not math part

• Dark blue represents 100 taking neither

250

100

50 taking science!

… next information

• Of the ones taking math, 40% are taking science

• .40 times 250 is 100

• Divide the freshmen into those taking math and those not

• Final answer 100 + 50 taking science

Communicating

• information• …. message, but also / often: want people to act

a certain way

• If you want teenagers to stop smoking, bad breath may be stronger dis-incentive than the chance of dying of lung cancer in many years.

• (return to math…)

Presentation of diagrams

• Important to define target audience– Generally not everyone– Here, we'll pretend it isn't me….

• What is level and experience of typical (?) US reader/viewer of diagrams?

Data dimension

• The data that is worth presenting in graphics form (as opposed to clear text) is generally complex: multi-dimensional.

• Dimension: measurement, extent, reach– the degree of manifoldness: time has 1 dimension,

space has 3….

• Edward Tufte (and others): – don't give data dimensions it doesn't have. Don't use

3D for bar graphs– read (borrow) his books

Minard chart

• Napoleon's army into and out of Russia– "….beat by General Snow and General Winter"

• chart shows– size of army– travel to and from Moscow– temperature– time– geography

• Many articles, alternative presentations, on-line

Map: height & depth

• Bad example– used Rainbow when it had no meaning– consider people who are color blind…

As with 3D bar charts when you only have

points, avoid rainbow, when the data is one-

dimensional(Note: shades of blue chart better for color-

blind visitors.)

Sign and dimension

• Previous example contrasted height on land with depth of the ocean.

• Next chart is problematic: one dimension of shading used for negative and positive values.– is this a problem?

Dimension

• Identifying dimension is important and may not be obvious.– Challenger disaster: problems were associated with

temperature.

• Values 'along' a dimension may be discrete or continuous or… forced into discrete (quantized) categories or discrete but many values– weight and height are continuous, but we round

(down or up) to a standard unit– registration is done by grouping credits earned

Excel: things to avoid AND things to consider

• 3D option for bar graphs and pie charts when there isn't the data for the extra dimension is misleading.

• Nice formatting trick– Conditional formatting: make the color and/or

border and/or font dependent on a formula– Use Format painter to copy

Time periodAsk• Out of how many?• Over what period of time?

– Is period of time meaningful (have the meaning you/the audience thinks it has)

• Analysis of costs of Bush tax cuts based on tax cuts expiring• Cost of the Medicare drug benefit was given originally for 10

year period including 2 years when it wasn't in force!• New Health Care Reform will roll out over several years

Cars versus planes

• Many people believe air travel more dangerous than car travel.

• Recent news on improvement in air travel (with regard to accidents, not delays, inspections, etc.)

• What do you think?

RisksReported versus publicized versus total number of

incidenceClaim: virtually all air traffic accidents are

publicized (and investigated and, perhaps, re-publicized). Very few car accidents are publicized to any extent.

Which cause more fatalities:US: ~40,000 (car) versus ~200 (commercial air

travel)

http://www.newton.dep.anl.gov/askasci/gen99/gen99845.htm

http://hazmat.dot.gov/riskmgmt/riskcompare.htm

Good to compute average over time. These are 1994-8.

Ask 'out of what?' What is appropriate 'universe'?passengers, miles traveled, (airplane departures)

Motor Vehicle 41,616 1 in 6,300 1.7 deaths per 100 million veh. miles

Commercial Air Carriers 169 1 in 1,568,000 0.7 deaths per 100 million aircraft miles0.19 deaths per million aircraft departures

New issue: Car accidents & texting• Note: need to check multiple sources.

Sites often are:– organizations pushing laws (which I may

agree with, but need to check sources)– law firms seeking clients for suits– government agencies—may need

interpretation– ?

• GREAT example for the diagram assignment

Recent study• Article on study:

http://articles.latimes.com/2010/sep/24/news/la-heb-distracted-driving-20100924 – Crunching the numbers, they calculated that if text

messaging had never been invented, there would have been 1,925 traffic fatalities per year due to distracted driving between 2002 and 2007. But in real life, they rose from 4,611 in 2001 to 5,988 in 2007.

• Abstract on study: http://ajph.aphapublications.org/cgi/content/abstract/AJPH.2009.187179v1 – Specifically, the dramatic rise in texting volume since

2005 appeared to be contributing to an alarming rise in distracted driving fatalities.

Risk

• Immediate – sun exposure may cause sun burn

• long-term (ever happen) – sun burns in youth may cause melanomas later

• cumulative effects of certain behaviors– constant sun may (also) cause melanomas, may also

affect skin– adding up effects

http://www.health-alliance.com/Cancer/skin/risk_factors.html

Mammogram

Screening test– test many women (practically all healthy)– abnormal test leads to more tests, maybe

treatment, some making a difference– General remark: 1 in 8 women will get breast

cancer

New study on mammagrams

• New York Times: http://www.nytimes.com/2010/09/23/health/research/23mammogram.html – Look at multimedia / graphic

• New England Journal of Medicine: summary: http://www.nejm.org/doi/pdf/10.1056/NEJMoa1000727

Possible factors

• [Mentioned in article]: treatments have improved. PERHAPS early diagnosis less critical.

• Costs associated with biopsies AND surgery for slow-growing cancers more important.

• Note: study only evaluated mortality.

ALL screening tests

• Issues of– false positive (person/case identified as

having condition when they don't)• increases when testing large number of well

people

– false negative (person/case identified as not having condition, when in fact they do)

– WILL COME BACK TO TESTING TOPIC

Homework

• Postings

• Complete diagram assignment.– Use imagination– Focus on communication of message– Consider structured picture. Annotations of

charts, ?

• Start to plan first project.