A September 2025 report analyzes voter-level ballot data from primary and general elections from 2020 to 2024, to better understand the vote-by-mail experience in Washington State, with particular attention to outcomes of ballot curing processes and rejection of ballots not cured. Several key research questions guide this report: To what extent are signature challenged ballots cured by voters? How do cure rates vary by voter demographics and geographic location?How have trends and patterns in ballot rejections varied over time? Do rates of ballot rejections vary by voter demographics or geographic location? How do the reasons for which ballots are rejected vary over time, voter demographics, and geographic location?

This September 2025 report found:

  1. Across primary and general elections from 2020 to 2024, 1.6 percent of ballots cast were challenged for a missing signature or a signature that did not match the signature on file.
  2. In primary and general elections since 2020, about 60 percent of ballots with signature challenges (missing signature or mismatched signature) have been cured before county elections officials submit election results to the State.
  3. Overall, 1.4 percent of all primary ballots cast and 1.0 percent of general election ballots cast were rejected across elections from 2020 to 2024.
  1. A very small percentage of all ballots cast were rejected for a signature that does not match the signature(s) on file – roughly about 0.5 percent of all ballots cast in any given primary or general election.
  2. An even smaller percentage of cast ballots – just 0.2 percent – are rejected for missing a signature on the ballot envelope.
  3. Roughly half of all ballots rejected in primary elections and in many general elections are rejected because they arrive late to county offices.
  1. We estimate that voters of color have higher ballot rejection rates than White voters. For example, in general elections from 2020 to 2024, Black (1.3 percent), Hispanic (1.5 percent), and Asian (1.5 percent) voters experienced ballot rejection rates much higher than White voters (0.9 percent).
  2. Self-identifying male voters have slightly higher ballot rejection rates than self-identifying female voters in both primary and general elections.
  3. Younger voters have a much higher ballot rejection rate than older voters. Roughly 4 percent of ballots cast by voters 18 to 25 years old from 2020 to 2024 were rejected, compared to less than 1 percent of ballots cast by voters 66 or over during that time. Younger voters are much more likely to have ballots rejected due to signature mismatch than older voters.

Download the full report: Rejected Mail Ballots Report