Statistical Analysis of the Post-Election Audit Data 2011 November Election

The Center for Voting Technology Research (VoTeR Center) at the School of Engineering of the University of Connecticut received the data gathered in the post-election audit performed in the State of Connecticut following the November 2011 election. The audits involved the randomly selected 10% of the districts and the audit returns were conveyed by the Office of the Secretary of the State (SOTS) to the VoTeR Center on December 22nd of 2011. The audit data received by the Center contains 887 records, where each record represents information about a given candidate: date, district, machine seal number, office, candidate, machine counted total, hand counted total of the votes considered unquestionable by the auditors, hand counted total of the votes considered questionable by the auditors, and the hand counted total, that is, the sum of undisputed and questionable ballots. This report contains several statistical analyses of the audit returns and recommendations. The VoTeR Center’s initial review of audit reports prepared by the towns identified a number of returns with unexplained differences between hand and machine counts. Audit returns included 45 records with discrepancies higher than 5, with the highest reported discrepancy of 40. It is worth noting that 75% (30 out of 45) of the records that were subject to the follow up investigation already contained information indicating that the discrepancies were due to the human error. Following this initial review the SOTS Office performed additional information gathering and investigation of those 45 records. The final information was conveyed to the Center on May 18th of 2012. The rest of the records (842 out of 887) discussed in this audit report are the original records reported by the towns. This report presents the analysis of 887 records (100%) in two parts.

  • First, we present analysis of 887 records (100%), among which 842 records (94.9% of 887) are original records, as reported by the districts, and 45 records (5.1% of 887) were revised based on the follow up conducted by the SOTS Office.
  • Second, we present analysis of the original 887 records (100%) prior to the SOTS Office follow up investigation. This is provided for completeness and comparison. For the revised records SOTS Office confirmed with the districts that the discrepancies were due to human counting errors. After the revised records were incorporated, the analysis shows that among 887 (100%) records there are 400 (45.1%) records showing no discrepancy, 244 records (27.5%) showing discrepancy of 1 vote, 107 records (12.1%) showing discrepancy of 2 votes, and 136 records (15.3%) showing discrepancy of 3 to 5 votes. The data presented in this analysis show that the average reported discrepancy is lower than the number of questionable votes on the ballots (1.1 versus 3.5). This analysis was performed on request of the Office of the Secretary of the State.

Full report: Nov-8-2011-HCA-V11

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