Data Analysis for PolicyMaking in Georgia
Module 4 · Disparate Impact Analysis › 4.4 Mail-in ballot rejection rates
Subsection 4.4

Mail-in ballot rejection rates

~3 min

Reading

Mail ballot rejection rate analysis is one of the clearest applications of disparate impact methodology in voting rights work. Rejection rates can be calculated precisely from administrative data, compared across demographic groups, and directly linked to policy choices about signature matching, ID requirements, and notice-and-cure procedures.

How to calculate mail ballot rejection rates

The calculation is straightforward:

Rejection Rate = (Rejected Ballots) ÷ (Total Mail Ballots Returned) × 100
Example: If a county received 10,000 mail ballots and rejected 150, the rejection rate is 1.5%.

To study disparate impact, you need rejection rates by demographic group. Because individual ballots are not race-coded, analysts typically aggregate to the precinct or county level and join to demographic data—similar to the RPV approach.

Comparing across counties

County-level comparison is the most accessible entry point. In Georgia, the Secretary of State publishes absentee ballot data showing the number of ballots issued, returned, and rejected by county. Calculate the rejection rate for each county, then join to ACS demographic data for that county to test whether counties with higher Black or Latino population shares have higher rejection rates.

Reasons for rejection

Georgia's absentee ballot data includes rejection reason codes. The most common reasons include: missing or defective signature; signature does not match the voter file; missing witness/notary (pre-SB 202); missing date; and returned after deadline. Signature mismatch is the most policy-addressable reason because it is the most discretionary—local election officials make the call.

Georgia 2020 data example

Researchers analyzing Georgia's 2020 general election absentee ballot data found that Black voters' mail ballots were rejected at approximately 2.7 times the rate of white voters. The leading rejection reason was signature mismatch, which accounted for the largest share of rejections and was the reason with the highest racial disparity. First-time voters also showed higher rejection rates than long-time voters, with significant overlap between the two groups.

Policy implications

Notice-and-cure procedures—which notify voters when their mail ballot has a curable defect and allow them to fix it—directly reduce rejection rates. Georgia's SB 202 modified notice-and-cure procedures. Analyzing whether the modification increased or decreased rejection rates, and whether any change was distributed equally across demographic groups, is a straightforward application of this module's methods.

Mail Ballot Rejection Rates by Voter Group — Georgia 2020 General Election (Illustrative) Rejection rate (%) 0.8% White voters 1.4% Latino voters 2.2% ⚑ Black voters 2.6% ⚑ First-time voters 1.1% Asian voters Top Rejection Reasons 1. Signature mismatch — 42% 2. Late return — 21% 3. Missing signature — 19% 4. Other defect — 18% Illustrative values based on reported Georgia 2020 research patterns. Signature mismatch shows highest racial disparity. Orange = flagged groups.
Diagram 4.4 · Mail ballot rejection rates by voter group — Georgia 2020 (illustrative). Black voters and first-time voters showed higher rejection rates. Signature mismatch is the most policy-addressable rejection reason.