Ballot Information File (bif) Report (Metadata Report)

2023 General Election, Broomfield County, CO

Audit Engine version:'v2.32.X'

Run Date: 2026-08-12 02:04:02.006281 Copyright (c) Citizens' Oversight

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Ballot Metadata Report Introduction

This report is a reconciliation of all metadata captured from various sources. The number of sources included may vary, based on the workflow and availability of image archives and the CVR. This report is essential when performing public oversight workflow audits, because it allows audit conductors to examine metadata to understand ballot style assignments, repeated ballots by ballot_id and repeated images, and to compare across all sources, images, CVR and any aggregated results. Each section of this report will have a separate introductory paragraph.

Table of Contents

• High Level Reconciliation
• Metadata Summary
• Sheet Count Summary
• Ballotids in BIA but not in CVR -- Precinct Report
• Ballotids in BIA but not in CVR -- Examples
• Card code analysis (use_card_code_as_style_num)
• Small Styles Report
• Hexstyle to style_num analysis (use_hexstyle_as_cvr_style)
• Summary Report by precinct
• Summary Report by batchid
• Summary Report by tabulator
• Ballots with alignment errors or unreadable barcodes
• cvr_dups_list ballot_ids
• bia_dups_list ballot_ids
• Ballot Image Archives Summary
• Ballot Image File Size Extremes
• Sheet Sizes

High Level Reconciliation

Metadata Summary

Ballotids in CVR but not in Image Archives

This report can provide hints about why the ballots images are missing.

Ballotids in CVR but not in BIA by cvr_file

Ballotids in CVR but not in Ballot Image Archives, Examples

First, 34 of 34 cases.

%% daf rows=34; cols=50; keyfield='ballot_id'; name=''

Created missing_images report: 'reports/US_CO_Broomfield_20231107_aimapper_missing_images.csv'

Card code analysis (use_card_code_as_style_num)

Important: style_nums with multiple hexstyles (needs investigation)

hexstyle is normally determined solely from the CVR (one contest-set per ballot_type_id). A style_num below has more than one distinct hexstyle among its ballots -- something other than ballot_type_id is causing the contest-set to vary (e.g. BMD vs nonBMD, or a sheet-specific vs full-ballot computation) and needs investigation before this style_num can be trusted for mapping.

None -- every style_num has exactly one hexstyle.

Remaining style_nums (single hexstyle)

Small Styles Report

This report provides an analysis of the number of ballots that are included in "small styles" and therefore, there is a threat that the voter could be linked to their ballot. For purposes of this analysis, a "Small Style" is defined as a style with fewer than k ballots in it. The worst case is if there is only one ballot in the small style, because that voter could be linked to their ballot if other information were cross-references with the cast vote record data. AuditEngine explicitly does not link voters to their ballots.

Very commonly, the reason for small styles is due to handling the federal-only ballots, which tend to be UOCAVA (Uniformed And Overseas Citizens Absentee Voting Act) voters. The privacy of these ballots can be easily improved by NOT splitting them by precinct, but instead by including them in one large virtual precinct.

• For 2023 General Election, Broomfield County, CO
• anonymity_parameter_k = 10.
• There were 0 BMD ballots that did not have a style_num in the cvr and were not examined during full_bif stage.
• There were 239 ballots with no style_num specified, likey because the images or cvr records are missing.
• There were 0 small styles detected, affecting 0 ballots.
• There were 0 split styles with multiple precincts per style.
• There were 0 mergeable styles, affecting 0 ballots.
• If merged, 0 small styles, affecting 0 ballots would remain.
• Ballots anonymizable by merging = 0.0000% of all 26,559 ballots

Summary for unified table

Small Styles

{closing}

Hexstyle to style_num analysis (use_hexstyle_as_cvr_style)

This report is another way to look at the styles in the election. The 'hexstyle' value is a description of the contests in the election. Each row in this table is a unique set of contests on the ballot. Sometimes, if the same set of contests is applicable to more than one precinct, a style will be defined for each precinct. Voter privacy can be improved by combining precincts that have the same set of contests if the "ballots" field is low.

Summary Report by precinct

This report simply provides a list of the mapping from the field specified to the styles.

Summary Report by batchid

This report simply provides a list of the mapping from the field specified to the styles.

Summary Report by tabulator

This report simply provides a list of the mapping from the field specified to the styles.

Introduction

This report details information about the ballot image archives provided by the election district. These ballot image archives are typically provided as ZIP archives, but they may also be PDF files with many 1000s of images of sheets in some cases. Here, we review the sizes of the images and whether there are any repeated ballot_ids. This does not examine the images to find repeats, but simply marks them as repeats if they have the same ballot_id. The ballot_id of each ballot sheet must be unique. If there are multiple-sheet ballots, they will have multiple images that are not kept together.

Ballot Image Archives Summary

Ballot Image File Size Extremes

End of Ballot Information File (bif) Report

2023 General Election, Broomfield County, CO

Audit Engine version:'v2.32.X'

Run Date: 2026-08-12 02:04:07.695326 Copyright (c) Citizens' Oversight

Return to Master Report Index