1 / 20

Let’s Not Forget About Accuracy

Let’s Not Forget About Accuracy. Henry E. Brady Class of 1941 Monroe Deutsch Professor of Political Science and Public Policy University of California, Berkeley . Accuracy and Security . Accuracy: Votes are properly recorded according to voter’s intention

hiero
Download Presentation

Let’s Not Forget About Accuracy

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. Let’s Not Forget About Accuracy Henry E. Brady Class of 1941 Monroe Deutsch Professor of Political Science and Public Policy University of California, Berkeley

  2. Accuracy and Security • Accuracy: Votes are properly recorded according to voter’s intention • Security: Votes are not changed because of misfeasance or malfeasance – mistakes or fraud

  3. A Word About Security • Note: • Risk = Threat X Vulnerability • Many discussions only consider vulnerabilities and not threats. • But it takes both to create a risk.

  4. Measuring Accuracy • Residual votes: • Number of ballots minus number of votes in a race • Example: 100 ballots & 97 votes so 3 residual votes • Residual votes are sum of: • overvotes (ballots with more than one mark for a contest, thus invalidating the vote) and • undervotes (ballots with no mark for a contest, thus not counting as a vote) • Residual vote rate -- Residual votes over number of ballots -- Example: 3/100 = 3%.

  5. Cause of Residual Votes • Not all residual votes are “errors” – sometimes people choose not to vote in a race: They intentionally undervote or overvote. • But for “top-of-the-ticket” contests, residual votes should be low – around ½% to 1%. • If two jurisdictions are similar except for voting systems and one has significantly lower residual vote rates than the other, then the difference is the performance of voting systems (technology, poll workers, administration).

  6. Table 1 – Average of Lowest Residual Vote Rate For Each County among Eight Propositions by Polling Place Voting System Types

  7. Comments and Caveats • Data are from preliminary canvas • Residual rates are by polling place voting system – but many votes are absentee • Two types of averages in the table: • Simple county averages • Averages weighted by number of ballots • Two counties omitted: • Monterey (used two types of systems) • Butte – Instructive story

  8. Further comments • Most rates less than 1.2% • High ones due mostly to two counties: • Los Angeles – 3.5% -- Ink-A-Vote • San Francisco – 4.0% -- ES&S Optech Eagle • Only three other small counties over 1.6%: • Sutter – 4.5% (Mark-A-Vote) • Mariposa – 6.5% (Sequoia AVC Edge) • Mono -- 8.5% (Sequoia AVC Edge)

  9. What’s Going on In Los Angeles? • Consider November 2004 data • Strong positive relationship between: • Percent minority and residual vote • But this seems to be the result of strong negative relationship between: • Percent high school graduates and residual vote

  10. What Causes these Relationships? • Consider Fresno’s “experiment” of going from Votomatic style punchcards in 1996 to optical scan with precinct count in 2000 • The people voting remained essentially the same, only the voting system changed. • Hence, difference in residual rates must be due to voting system.

  11. Comparing Los Angeles with Other Counties • Compare residual vote rates with adjoining Counties. • If counties are similar, then those with higher residual vote rates have voting systems that are performing badly. • Are counties similar?

  12. Table 2: Residual Vote Rates for Los Angeles and Adjacent Counties Note: In November 2004 the residual vote rate is for the presidential race. In November 2005, the residual vote rate is the lowest among all eight propositions. Sources: California Secretary of State’s Web Page and Los Angeles Counties web page.

  13. Maybe Los Angeles is Just Different? • Again consider November 2004 data. • Look at precincts at LA border and compare them with contiguous precincts in adjoining counties. • People should be similar, but voting systems are different. • If difference in residual votes, then due to voting systems.

  14. Conclusions • Some voting systems more accurate than others, • Residual vote rates can identify problems with voting systems, • Better data, such as breaking out undervotes and overvotes by absentee, early-voting, and polling place voting in each precinct, would be very useful for assessing accuracy, • The state of California should, after adjusting for differences in voters across counties, regularly prepare a “Voting Performance Report Card” to identify systems with low residual vote rates and those with high rates, • Accuracy should be given as much weight as security in considering the performance of voting systems.

More Related