Graphing Charts (Dr. Jackson Presentation)

Graphing Charts, and Using Online Cambridge Historical Statistics of the

U.S. Graphing FunctionThomas Jackson

HIS 391 Skills and MethodsSpring 2016

THE NEXT 12 SLIDES ARE From Dr. Steven Ruggles, University of Minnesota: “The Basics … Graphical Displays Should:”

• induce the viewer to think about the substance rather than about the methodology, design, the technology of the graphic production, or something else• avoid distorting what the data have to say• present many numbers in a small space

Continued...

The Basics … Graphical Displays Should: (2)• make large data sets coherent• encourage the eye to compare different pieces of

data• serve a clear purpose• be closely integrated with the statistical and

verbal descriptions of a data set.

Lie Factor• Lie Factor = size of effect shown in graphic size of effect in data

• Greater than 1.05% or less than .95% indicates substantial distortion, far beyond minor inaccuracies in plotting.

NYT: Fuel economy “graph”

Note to students: this graph hugely distorts improvement in fuel standards, which did rise by less than 10 mpg over a decade, an improvement of 50%, but way overstated in the plotting . . . TJ

Maps: just bad graphs

Chart-junk. What is it? Anything that doesn’t NEED to be included in the chart.

• Line Graph – BEST FOR TRENDS! tj• x-axis requires quantitative variable• Variables have contiguous values• familiar/conventional ordering among ordinals

• Bar Graph• comparison of relative point values

• Scatter Plot• convey overall impression of relationship between two

variables• Pie Chart

• Emphasizing differences in proportion among a few numbers

Bar charts

• Best for comparing different things during the same time period

• Neither the bars nor the axis should be interrupted • Axis should usually include zero (some exceptions) • Avoid 3-D effects, can be misleading

Line graphs• Best for showing change over time • Can indicate trends • Use a different color and symbol for each line • Avoid too many lines • When to use log scale

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Percent of Persons Aged 65+ Residing with their Own Children aged 18+:

United States 1850-2000

Labeling: Title

Height/width should be about 3:4 (same as old-fashioned TV

Labeling: lines

Percent of the Labor Force Employed in Agriculture, United States, 1800-2000

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Figure 1: Percent of elders in intergenerational families

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Argentina

Brazil

Chile

Colombia

Costa Rica

Ecuador

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Mexico

Philippines

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Vietnam

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Uganda

Venezuela

Too many lines!

Percent Female; Scientists and Engineers

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IPUMS Graph from “A Century of Women in Science and Engineering,” History Day project by Abby Norling- Ruggles, age 12

Prof. Tom Jackson . .. How to Lie and Spin with Numbers—Is Post-Cold War Defense Spending Out of Control?

Change the relevant comparison or denominator.Manipulate the aspect ratio of a graph.Ignore context: (as with federal spending which automatically increases with an aging population drawing upon Social Security)

“America’s staggering defense budget,” in chartshttps://www.washingtonpost.com/news/wonk/wp/2013By Brad Plumer January 7, 2013/01/07/everything-chuck-hagel-needs-to-know-about-the-defense-budget-in-charts/ TJ’s added text boxes in RED

Wow, Korea and the H Bomb--TJ

In the quagmire of Vietnam

Reagan’s nuclear build up and 600 ship Navy

Clinton’s post-Cold War luck and budget balancing

AND NOW A CONSERVATIVE ASSESSMENT: “The Myth That America Spends Too Much on Defense”by Kyle Becker “defense spending has plummeted as a percentage of GDP, as the graph below illustrates.” [emphasis added]

https://rogueoperator.wordpress.com/2012/01/06/the-myth-that-america-spends-too-much-on-defense/

• NB: GDP=Gross Domestic Product

Different percentage: total federal spending

This one is better . . . From the Heritage Foundation, showing BOTH absolute spending and relative GDP Percentages.

And now . . . The Assignment!!

From the vast statistical treasure trove of the Cambridge University Press Online Historical Statistics of the United States, (see course guide HIS 391 Case Studies), SELECT a table to plot. Use the “graph” function to show and explain an important trend.1. Shoot for a major trend like the graph we considered in ATF of

migration to California from 1910 to 1950— explore that time frame (or one that intrigues you).

2. There is a master list of the various tables in ms Word files. BOLDED tables I see have potential for you.

3. Limit the years and the “Series” items, using the graph function and “specific rows.”

4. Format the graph using this as a guide, write 2 pages about the significance and possible causes of the trend, and present in class on next Wednesday

HERE’S WHAT YOU CLICK!!---

STUDENTS! You want to pick something that will reveal an important trend over time that bears somewhat on the changes of the Interwar Period or mid-century America. The big series are listed on the left. I have selected “Labor” under “Work and Welfare”

Hey, this one looks good!

You don’t see ALL the industries, so you have to “Jump” to see the rest.

JUMP!!-

Results with NONE unchecked! And WIDE aspect ratio. Not too revealing!

Even with a change in the aspect ratio (though better on whole Labor Force)

Leaving in “Total” has the effect of flattening everything else, making it seem like changes in most industries were minor.

De-Select Total and some small categories and trends (but let’s keep Government)

Remember the rule about aspect ratios in a graph. Don’t overdramatize or underdramatize trends. Pull down on the little square to change the picture to 4:3 in Power Point:

With adjusted aspect ratio (just drag the squares down) this shows the dramatic rise in government employment in World War II (and the early New Deal) but other trends are still a bit flattened.

Let’s take out Government and see trends in the private economy! Wow, look at manufacturing, but remember, 40%+ of that is government war contracts: see the tanks, ships, bombers, not yet electric vacuum cleaners, etc. I also adjusted the contrast and brightness so you could see all the lines (just double click on the picture in Power Point).

Or go under the “Format” menu to see picture corrections and Artistic Effects!

This effect is called “Photocopy” I like it.

Here is “dayglow”

Once you have your graph, you can now write a narrative of the most important changes of the Great Depression and World War II, with a glimpse at the shape of the Post 1945- world!

Why not look at consumption? Way too many variables: what will be most revealing???

IMPORTANT: You can limit the years by entering “specific row #s”! That way I avoided compression from new car sales after 1945!

HERE!!

This one took about an hour to figure out how to format. I was interested in a variety of personal expenditures by consumers from the beginning of the Great Depression to the end of WWII. What did Americans cut back on? What did they refuse to do without? Why does domestic service rise so dramatically along with shoes and tobacco, while doctors remain fairly flat and new autos just plummet? Too many lines? Maybe just plot new cars, tobacco, domestic servants, and doctors? If you put “food” in the graph, all the rest gets compressed down.