What is a common failure rate in postal voting?

Question

According to reporting by Omroep West, a postal voting trial in The Hague failed with over half of the ballots ruled invalid. The trial is an experiment for the upcoming general election in the Netherlands in which over 70s are allowed to cast their ballot by mail. Of the mock ballots cast in the trial, over half were invalid. Reasons named in the article are: lacking a signature or being submitted in the wrong envelope. Extrapolating to the expected number of mail-in ballots in the real election, the trial leader warns up to 650.000 people may cast an invalid postal vote.

This seems very odd to me, especially considering other elections abroad where postal voting has been used successfully. As such, I'm wondering what the failure rates are with postal voting in other countries. Are postal votes generally ruled invalid at a higher rate compared to in-person voting in the same election?

Answer 1

In the U.S., the rate at which mail in ballots were invalidated in 2020 was about 1.0% and it was about 1.4% in 2016 and 2018.

This is a somewhat tricky comparison, however, because the U.S. involves 51 different sets of laws governing when mail in ballots are valid, and there is wide variation from state to state (as shown at the link above) in invalidity rates for mail in ballots under the laws of different states, ranging from 0% to 6.42% in 2016 and from 0.34% to 7.56% in 2018 (only incomplete state by state data is available for 2020).

Some small percentage of ballots are also invalidated in in person voting, for a variety of reasons, such as selecting more than one candidate when only one vote for a post is authorized by law, or for writing in a candidate not certified as a write in candidate.

In contrast, in a Dutch election there would be only one applicable statute.

One pertinent distinction is that the Dutch election process would apply only to voters over the age of 70 years of age, while the U.S. figures, under U.S. election laws, apply to voters of all ages, or even when age or disability is a condition to absentee ballot access, to a much broader age range than is allowed in the Dutch election.

It is not unreasonable to guess that people over the age of 70 in the Netherlands who elect to vote by mail rather than to vote in person, as is customary there, are disproportionately suffering from serious physical or minor cognitive disabilities (even within the subset of potential voters age 70 or above) and that this highly biased set of mail-in voters contributes greatly to the invalid ballot rate.

It is also likely that since mail in ballot is not the historical norm in the Netherlands, that officials have not used particularly clear instructions and forms to communicate to mail in voters what they must do, something that could be addressed with the better mail in ballot process and ballot design found in jurisdictions where mail in ballots are more common.

Answer 2

The Electoral Commission in the UK published a report in 2017 (UKPGE 2017 Electoral Data Report) which analysed the 2017 General Election. (The report also gives statistics for 2010 and 2015.)

In brief (2017):

• There were over 32 million votes cast and 8.4 million postal votes issued;
• For ballot box (i.e. non-postal) turnout, 0.2% of the ballots were rejected;
• For postal votes, 2.4% were rejected;
• Mismatched information (signatures / DoB) accounted for 48.5% of those rejected postal votes;
• Missing forms accounted for 33.2% of the rejections;
• Missing information accounted for 18.3%.

The section on postal voting concludes with:

It is worth noting that these percentages represent very small numbers of postal votes. For example, although 48.5% of rejected postal votes were rejected due to mismatched information, this represents 1.2% of covering envelopes received and 0.3% of all votes cast. The vast majority of postal voters did correctly file their returns.