Department of Politics and Government Illinois State University Gary Klass Department of Politics and Government Illinois State University

Data Presentation Standards “Graphical Excellence” -- Edward Tufte well-designed presentation of data of substance, statistics and design complex ideas communicated with clarity, precision and efficiency the greatest number of ideas in the shortest time with the least ink in the smallest space. Best example: Baseball statistics

Draw Conclusions from Meaningful Comparisons One year changes in crime rates are not very meaningful Rates (and averages) tell more than counts (crimes rates, not crime counts)

Defense presentation at John Gotti trial: This Chart is described in Tufte, Envisioning Information, p. 31. Reconstructed by Christy Zlatos, http://hdl.handle.net/2376/1976

Data Presentation Principles Show the data Meaningful comparisons Minimize the ink to data ratio Tell the Truth -- Avoid data distortion Sort by a meaningful variable Charts should be self-contained

Show the Data Illinois State Police, Crime in Illinois 2007 Annual Uniform Crime Report   http://www.isp.state.il.us/crime/cii2007.cfm

Illinois State Police, Crime in Illinois 2007 Annual Uniform Crime Report   http://www.isp.state.il.us/crime/cii2007.cfm

The problems with that chart Time goes left to right Scaling distortion Unnecessary 3-D ink Better not to use different colors to measure the same thing. Year to year changes are usually not important.

Arrestee Drug Abuse Monitoring (ADAM II): Results for 2007 Justice Research and Statistics Association October 16 and 17, 2008 Dana E. Hunt, PhD October 17, 2008

A Ten-line Chart

Robbery Rates, Ten Largest Cities, 1985-2007 *BJS: Data Online

Sort the Data! By the most meaningful variable The Alphabet is not the most meaningful variable Time goes left to right

Sort Data by the most important variable The Alphabet is not the most important variable

Arrestee Drug Abuse Monitoring (ADAM II): Results for 2007 Justice Research and Statistics Association October 16 and 17, 2008 Dana E. Hunt, PhD October 17, 2008

Revised Chart

Evaluating Recent Changes in Homicide and Robbery Rates Richard Rosenfeld Brian E. Oliver Department of Criminology and Criminal Justice University of Missouri-St. Louis http://jrsa.metapress.com/content/0131277x064548t2/fulltext.pdf JUSTICE RESEARCH AND POLICY, Vol. 10, No. 2, 2008 © 2008 Justice Research and Statistics Association 49-65

Sorting data by least meaningful variable ICJIA, “Trends in Illinois crime: 1995-1999” http://www.icjia.state.il.us/public/pdf/tiupdate/crime99.pdf

Time Goes Left to Right On Bar Charts Use shade, not color, to distinguish years (if necessary) Make the “years” the data series: position years on adjacent bars

Evaluating Recent Changes in Homicide and Robbery Rates Richard Rosenfeld Brian E. Oliver Department of Criminology and Criminal Justice University of Missouri-St. Louis http://jrsa.metapress.com/content/0131277x064548t2/fulltext.pdf JUSTICE RESEARCH AND POLICY, Vol. 10, No. 2, 2008 © 2008 Justice Research and Statistics Association 49-65

Tell the Truth Avoid Data Distortion

NEW YORK STATE CRIMINAL JUSTICE, 2008 Crimestat Report http://criminaljustice.state.ny.us/pio/annualreport/2008crimestatreport.pdf

Illinois http://www.icjia.state.il.us/public/pdf/tiupdate/crime99.pdf

NEW YORK STATE CRIMINAL JUSTICE, 2008 Crimestat Report

Graphical distortion Wall Street Journal editorial, "No Politician Left Behind

Revised Note 8th grade reading ‘90: 260 ‘04: 259

Revised: Note: Bars depict volume; lines depict rate Sources http://nces.ed.gov/nationsreportcard/naepdata/ --long term trend Note: Bars depict volume; lines depict rate

Minimize the ink to data ratio Never use 3-D Avoid all ChartJunk

Don’t use Pie Charts!!!!!!! Never use Pie Charts Never ever use 3-D Pie Charts Never compare data across two pie charts The same thing goes for cones, pyramids and donuts

Page 1 JRSA, 2008 Community Corrections and Alternatives to Incarceration A Heartland Response to Crime Kansas 2003 Senate Bill 123 Thursday, October 16, 2008 Helen Pedigo Executive Director Kansas Sentencing Commission

Better but not great… Mentally Ill Offenders in Prison: Using Data to Examine Issues, Improve Practices Lettie Prell Director of Research Iowa Department of Corrections JRSA, 2008

JRSA 2008 Arizona Homicide Study Matt Bileski, Research Analyst Statistical Analysis Center

Two pie charts are worse than one

Revised Chart: Parolee Employment Status, 2007-8

UNIFORM CRIME REPORT, State of New Jersey 2007: http://www.state.nj.us/njsp/info/ucr2007/index.html

Revised chart

the greatest number of ideas in the shortest time with the least ink in the smallest space.