Box Plots: A Political Example

BOX PLOTS

Box plots are used to provide information to you about the sizes of a variable in a data set. In the example below, the sizes of the variable – on budget deficit as a percentage of Gross Domestic Product – are compared for differing values of a second variable, a categorical variable describing the controlling political parties of the President, Senate, and House of Representatives. The heavy horizontal line in each box is plotted at the median value for the data group. The top of the box is plotted at the 75th percentile while the bottom of the box is plotted at the 25th percentile. The top and bottom whiskers end at the most extreme values of the points not calculated to be outliers. The circles represent points calculated to be outliers.

The data is from a deficit by political party data set. The deficit by political party data set contains data on the on balance deficits as a percent of the gross domestic product for the years 1940 to 2015, and the political parties controlling the presidency, the senate, and the house for the years 1939 to 2014. The data for the deficit and the gross domestic product are from the Office of Management and Budget and can be found at http://www.whitehouse.gov/omb/budget/Historicals (except the first 8 values for the deficit data, which were from a series published earlier). Before 1978, the budget year ran from July 1st to June 30th. From 1978 onward, the budget year ran from October 1st to September 31st. The tables contain a one quarter correction between the years 1977 and 1978, which I have ignored. The year with which the deficit and gross domestic product are associated is the year at the end of the budget year for which the deficit and gross domestic product are calculated.

For 1940 to 2011, the data for the controlling political parties of the president, senate, and house were taken from the website of Dave Manuel,
http://www.davemanuel.com/history-of-deficits-and-surpluses-in-the-united-states.php
, a good resource on the history of the deficit.  The last three years were taken from the website https://en.wikipedia.org/wiki/United_States_Presidents_and_control_of_Congress

We look at the size of the deficit (-) / surplus (+) using the political affiliations of the President and the controlling parties of the Senate and the House of Representatives. Below are two sets of box plots, one set for the full number of years in the data set and one set for a reduced number of years. Since the budget is created in the year before the budget is in effect, the deficit (-) / surplus (+) percentages are associated with the political parties in power the year before the end of budget year.

Box plots of deficit / surplus as a percentage if GDP by party of president, senate, and house

The first set of box plots are for the years 1940 to 2015 with regard to the budgets and for the years 1939 to 2014 with regard to the party affiliations. We can see in the first set of box plots that in the years of a Democratic President, House, and Senate, there were some very large deficits. These large deficits occurred during World War II. The large deficit under a Republican President and Democratic Senate and House was in 2009, which budget was associated with the last year of the G. W. Bush presidency. The large surplus in the years of a Democratic President and a Republican Senate and House was in the year 1948, when Truman was president.

The second set of box plots are for the years 1947 to 2015 with regard to the budgets and for the years 1946 to 2014 with regard to the party affiliations. With the years of extreme deficits removed, there is a clearer picture of how the differing party combinations perform in more normal years.  The rather large deficits under the Democrats controlling all bodies were under Obama in his first term, as were the four deficits from 2012 to 2015, when Obama was president, the Democrats controlled the Senate, and the Republicans controlled the House.  Obama inherited a dangerous economic situation and got us through the economic turmoil, but in the process, Obama was running quite large deficits.

The data is here:

comb.party.39to14        defsur.40to15
“1939” “DDD”             “1940” “-3.59917”
“1940” “DDD”             “1941” “-4.90272”
“1941” “DDD”             “1942” “-14.78378”
“1942” “DDD”             “1943” “-30.83472”
“1943” “DDD”             “1944” “-23.29589”
“1944” “DDD”             “1945” “-22.00542”
“1945” “DDD”             “1946” “-7.62084”
“1946” “DDD”             “1947” “1.22684”
“1947” “DRR”             “1948” “4.0015243902439”
“1948” “DRR”             “1949” “-0.252890173410405”
“1949” “DDD”             “1950” “-1.68458781362007”
“1950” “DDD”             “1951” “1.31337813072694”
“1951” “DDD”             “1952” “-0.951048951048951”
“1952” “DDD”             “1953” “-2.16993464052288”
“1953” “RRD”             “1954” “-0.722207892700542”
“1954” “RRD”             “1955” “-1.00737100737101”
“1955” “RDD”             “1956” “0.569476082004556”
“1956” “RDD”             “1957” “0.560103403705299”
“1957” “RDD”             “1958” “-0.695762175838077”
“1958” “RDD”             “1959” “-2.39319620253165”
“1959” “RDD”             “1960” “0.0934404784152495”
“1960” “RDD”             “1961” “-0.693937180423667”
“1961” “DDD”             “1962” “-1.00528199011757”
“1962” “DDD”             “1963” “-0.645890521556596”
“1963” “DDD”             “1964” “-0.980540051289787”
“1964” “DDD”             “1965” “-0.225130153369917”
“1965” “DDD”             “1966” “-0.396470136846144”
“1966” “DDD”             “1967” “-1.50322118826056”
“1967” “DDD”             “1968” “-3.08017346825309”
“1968” “DDD”             “1969” “-0.0509009467576097”
“1969” “RDD”             “1970” “-0.829282241921647”
“1970” “RDD”             “1971” “-2.33181452693648”
“1971” “RDD”             “1972” “-2.14022140221402”
“1972” “RDD”             “1973” “-1.12094395280236”
“1973” “RDD”             “1974” “-0.484457004440856”
“1974” “RDD”             “1975” “-3.35899664721222”
“1975” “RDD”             “1976” “-3.87644528849913”
“1976” “RDD”             “1977” “-2.46006704791954”
“1977” “DDD”             “1978” “-2.43174435958213”
“1978” “DDD”             “1979” “-1.5408560311284”
“1979” “DDD”             “1980” “-2.61370137299771”
“1980” “DDD”             “1981” “-2.35470303339281”
“1981” “RRD”             “1982” “-3.63921663297022”
“1982” “RRD”             “1983” “-5.86540905368388”
“1983” “RRD”             “1984” “-4.68781623153208”
“1984” “RRD”             “1985” “-5.18686774072686”
“1985” “RRD”             “1986” “-5.24459337316197”
“1986” “RRD”             “1987” “-3.52161274807085”
“1987” “RDD”             “1988” “-3.73028651238579”
“1988” “RDD”             “1989” “-3.68761220825853”
“1989” “RDD”             “1990” “-4.693470395293”
“1990” “RDD”             “1991” “-5.26014304184874”
“1991” “RDD”             “1992” “-5.29006791303402”
“1992” “RDD”             “1993” “-4.42096278090921”
“1993” “DDD”             “1994” “-3.59554308260858”
“1994” “DDD”             “1995” “-2.9854682596197”
“1995” “DRR”             “1996” “-2.18091573392828”
“1996” “DRR”             “1997” “-1.21652206714447”
“1997” “DRR”             “1998” “-0.333899137892527”
“1998” “DRR”             “1999” “0.0199779191420009”
“1999” “DRR”             “2000” “0.851382511184249”
“2000” “DRR”             “2001” “-0.306684588152888”
“2001” “RDR”             “2002” “-2.91811085879249”
“2002” “RDR”             “2003” “-4.75097949242879”
“2003” “RRR”             “2004” “-4.69864169548169”
“2004” “RRR”             “2005” “-3.82965187098977”
“2005” “RRR”             “2006” “-3.17507873756823”
“2006” “RRR”             “2007” “-2.38918096195603”
“2007” “RDD”             “2008” “-4.3504785661994”
“2008” “RDD”             “2009” “-10.7509053320938”
“2009” “DDD”             “2010” “-9.26715545494476”
“2010” “DDD”             “2011” “-8.88732833957553”
“2011” “DDR”             “2012” “-7.16843865428771”
“2012” “DDR”             “2013” “-4.35807759681418”
“2013” “DDR”             “2014” “-2.99182355166293”
“2014” “DDR”             “2015” “-2.61579248907512”

The code for the plot is here:

function () {
par(mfrow = c(1, 2), oma = c(2, 2, 4, 2) + 0.1)
boxplot(defsur.40to15 ~ comb.party.39to14, cex.axis = 0.8)
title(main = “Percentage of GDP – 1940 to 2015\nPolitical Parties – 1939 to 2014”,
xlab = “President, Senate, House”, ylab = “Percentage”,
cex.main = 1, font.main = 1)
boxplot(defsur.40to15[8:76] ~ comb.party.39to14[8:76], cex.axis = 0.8)
title(main = “Percentage of GDP – 1947 to 2015\nPolitical Parties – 1946 to 2014”,
xlab = “President, Senate, House”, ylab = “Percentage”,
cex.main = 1, font.main = 1)
mtext(“On Budget Deficit as a Percetage of GDP\nGrouped by Political Party Controling the Presidency, Senate, and House\nParty Lagged One Year”,
side = 3, cex = 1, font = 1, outer = T)
}

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