When performed by professionals in criminal cases or legal proceedings, signature verification can take hours. But election employees in many states must do the job in as little as five seconds. [...] In 2016, mismatched signatures were the most common reason that mail ballots were rejected, according to federal officials. With record numbers of people voting by mail this cycle, ballots thrown out for signature problems and other issues have the potential to decide races where the margin of victory is slim.

That's the last one, I won't add any further updates.

NPR.org's More Than 550,000 Primary Absentee Ballots Rejected In 2020, Far Outpacing 2016 mentions:

Most absentee or mail-in ballots are rejected because required signatures are missing or don't match the one on record, or because the ballot arrives too late.

In the US is signature matching done for most or all mail-in ballots? Is it also done for in-person voting? Is it judged simply by any random volunteer, or only by someone "skilled in the art"? Is the same person who checks the signature also the one who counts the vote, or is signature rejection vote-agnostic?

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    @BobE in this particular case there is one underlying issue and trying to stretch this out over several or even six different question posts would be counterproductive as it would lead to fragmented answers, duplication and even questions closed as duplicates (which often happens when a posted question is answered elsewhere even if the the question is not exactly the same). Based on experience asking several thousand SE questions I've decided that for this topic it's best to keep it all in one place. Six seaprate question posts would not the way to go here.
    – uhoh
    Aug 22, 2020 at 22:30
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    Wouldn't comparing signatures violate the rights of people who don't draw their signature the same way each time?
    – endolith
    Aug 22, 2020 at 22:39
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    @endolith that's a real problem, and in mail-in voting there is no way to find out one's signature is being challenged and to have a chance to try once more.
    – uhoh
    Aug 22, 2020 at 22:43
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    @BobE endolith said draw their signature the same way each time, not spell their signature the same way each time. Aug 23, 2020 at 4:14
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    @uhoh see douglas.co.us/elections/voter-service-and-polling-centers/… for example of how to "cure" defective signature. Also addresses "draw"
    – BobE
    Aug 23, 2020 at 4:20

2 Answers 2


You'd need to go state-by-state to see exactly how each state handles their elections. Different states may well do things differently.

In general, however, signature matching is something that is done for absentee ballots not for in person ballots. Generally, the signature appears on an inner envelope on a ballot that is mailed in. The election official examines that outer envelope to verify the postmark (showing that the ballot was mailed in before the deadline) along with the signature (showing that the ballot was completed by the voter). If everything checks out, the envelope is opened and the actual ballot inside is taken out and counted. If not, the ballot is set aside.

Ballots are essentially never counted by a human so the person examining the signature would never count a ballot. It would generally be a different person that fed the ballot into the counting machine. One issue that does come up is that knowing a person's name and where they are registered, you can often make a pretty good guess about how that person is voting. If someone has a stereotypically African American name and is registered to vote in Detroit, for example, you can reasonably infer that their vote will likely be for Biden.

The amount of training that someone examining signatures would receive will depend heavily on the state and what you mean by "skilled in the art". It is unlikely that any state is going to have, say, forensic handwriting analysts comparing millions of mail-in ballots (and that ignores those that criticize handwriting analysis as junk science). Plus, you only have a handful of known signature to compare against where someone appearing in court as an expert witness would generally review a much larger sample of known signatures. So verifying the signature is bound to be at least somewhat subjective.

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    U said: "In general, however, signature matching is something that is done for absentee ballots not for in person ballots" I can't speak for any states other than PA and Ohio. In the past, in both states, when I voted in person my signature was compared with my registration signature as well as the signature I used at the last election.
    – BobE
    Aug 22, 2020 at 15:41
  • I think that you have confused the envelopes. For absentee and mail-in-ballots there are two envelopes. The outer envelope, bearing a postmark, does not have a signature. The inner envelope (that does not have any postage or postmark) bears the validation or authentication information, part of which is the signature.
    – BobE
    Aug 22, 2020 at 15:46
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    @BobE - You're right, I did mean to say inner ballot. That's fixed. And I changed "one" to "a handful" (depending on whether the voter has a license and has voted in the past in that juristiction). It's still much less than a handwriting expert would want (and that assumes you believe that handwriting analysis is a valid scientific endeavor). And they spend much less time than a handwriting expert would spend. Aug 22, 2020 at 16:00
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    @BobE - Is it possible? Sure, I suppose (though I'd expect the poll monitors to object if someone objected). But it's not part of the official process, not every ID would have a signature, and poll workers get a couple hours of training at most-- not nearly enough to do any sort of meaningful handwriting analysis. Aug 23, 2020 at 2:59
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    @BobE - Is it possible? Sure. But if the picture matches and the address matches and the poll watcher isn't allowed to touch the ID to see the rather small signature and the challenger has no training in signature analysis, it's tough to form a reasonable belief that the voter is invalid based on the signature. If the photo doesn't match or the address is wrong, that can produce a challenge. But the question is about the normal process not something that might happen in some exceptional corner case. Aug 23, 2020 at 4:25

Confining my answer to just the title question (s):

... are signatures always compared by a volunteer to previous signature on record?

a) not necessarily a volunteer, more often than not the team doing the signature comparisons are paid. That said, yes, the signatures are compared with other on-record signatures of the same person.

Is there any training for this?

Yes, however the requirement for training likely varies between jurisdictions.

ETA: Colorado Signature Verification Guide

  • Just fyi I've added one more news item to the question. It doesn't change the question nor affect your answer, but you might find that it adds additional context.
    – uhoh
    Oct 28, 2020 at 21:39

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