1 / 33

Gary Klass Department of Politics and Government Illinois State University

Gary Klass Department of Politics and Government Illinois State University. Just Plain Data Analysis. Part II Statistical Fallacies Gary Klass Department of Politics and Government Illinois State University. Statistical Fallacies. An argument:

dore
Download Presentation

Gary Klass Department of Politics and Government Illinois State University

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

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

  2. Just Plain Data Analysis Part IIStatistical Fallacies Gary Klass Department of Politics and Government Illinois State University

  3. Statistical Fallacies An argument: • Premises (evidence and reasoning) in support of a conclusion An argument fallacy: • When the premises, even if true, do not support a conclusion (Examples: false cause, slippery slope, ad hominem, straw man, red herring…). A statistical fallacy: • When the data do not support the conclusion.

  4. Cherry Picking: How President Bush Lowered the Poverty Rate (Bill O’Reilly)

  5. Cherry Picking: Distribution of 248 z-scores in 17 political economy studies (Tufte, Beautiful Evidence)

  6. Cherry Picking: Cumulative % change in income tax revenues* after Reagan and Clinton tax changes * Constant dollars

  7. Measurement Reliability:Two Measures of Violent Crime (per 1,000 population)

  8. Measurement Reliability\ Hawthorne Effect: American National Election Study

  9. Reserve Causation: Prosecution Rate of Public Officials and Voter Turnout, 1980-2004

  10. Reserve Causation: Felony Arrest Ratio and Violent Crime Rate, 2008: New York Counties (excl. NYC)

  11. Population Mortality: Enrollment and First International Science Study Results, Final Year of Secondary School

  12. The Trend is not your Friend: Average Contract Price of New One-Family Houses (2000 dollars)

  13. Regression Artifact: Senate Oil Price Speculation Bill and Crude Oil Prices*

  14. Rate of Change Fallacy:

  15. Rate of Change Fallacy: "Minorities in the U.S. increased their levels of homeownership at a faster clip than whites during the recent housing boom." -WSJ 5/13/09

  16. Graphical Distortion: Average Tuition and Fees: 4-year Public and Private Universities

  17. Graphical Distortion“Federal spending on K-12 education will top $41 billion in 2004. Add in state and local spending, and the figure rises to a record half-trillion dollars. That's double the amount spent in 1990 ……The negligible impact of this ever-increasing cash infusion on reading scores is illustrated in this chart:” -WSJ 2/15/04

  18. Revised

  19. Revised: Note: Bars depict volume; lines depict rate

  20. Dominant Denominator • “Bill Clinton and a GOP Congress balanced the budget by withdrawing a ‘peace dividend’ at a time when al Qaeda was declaring war” (2004). --WSJ 8/9/04

  21. Dominant Denominator: Clinton defense budgets: % of GDP and in constant dollars

  22. Does Giuliani deserve credit for NYC’s falling crime rate? • “Crime halved under Mr. Giuliani and murders fell by two-thirds, transforming New York from one of the most dangerous cities in America to one of the safest.” “From America's mayor to America's President?,” The Economist.com <http://www.economist.com/world/na/displaystory.cfm?story_id=9119759> (3 May, 2007)

  23. New York City Crimes, 1993-2001(Thousands)

  24. Counter Arguments: • William Bratton, not Giuliani, deserves credit* • Regression artifact – end of crack epidemic • Decline started under Dinkins* • Crime went down in other cities too (Freakonomics) • Most of the reduction was for minor crimes* • Bad data: CompStat led to underreporting* • The economy improved* • Dinkins hired more officers (Freakonomics) * Wayne Barrett .

  25. Dinkins? Violent Crime Rates, New York City, 1985-2007(per 100,000 population)

  26. Other Cities? Robbery Rates, Ten Largest Cities, 1985-2007*BJS: Data Online

  27. Other Cities? FBI\UCR Violent Crime Rates: 69 Largest Cities,2007 (population > 250,000)

  28. Just minor crimes? Violent and Property Index Crimes (thousands) -52%

  29. Bad Data? FBI and NCVS Violent Crime Rates, 2007 (population > 250,000)

  30. Bad Data? Murder Rates: New York and 69 Largest Cities, 2007(population > 250,000)

  31. The Economy?

  32. Police Hiring? Sworn Officers, New York City Police Department, and Violent Crime Rate 1992-04 General Accounting Office. “COMMUNITY POLICING GRANTS COPS Grants Were a Modest Contributor to Declines in Crime in the 1990s” http://www.gao.gov/new.items/d06104.pdf

  33. Police Hiring? Change in Crime Rates and Sworn Police Personnel, in the 1990s, 58 Largest Cities

More Related