In my previous post I explained the preliminary conclusions from the three experts engaged by New Hampshire to examine an election anomaly in the town of Windham, November 2020. Improperly folded ballots (which shouldn’t have happened) had folds that were interpreted as votes (which also shouldn’t have happened) and this wasn’t noticed by any routine procedures (where either overvote rejection or RLAs would have caught and corrected the problem)–except that one candidate happened to ask for a recount. At least in New Hampshire it’s easy to ask for a recount and the Secretary of State’s office has lots of experience doing recounts.
Let’s consider these issues one at a time.
Ballot folds interpreted as marks
National standards for voting machines say that creases should not be interpreted as votes. The “Voluntary Voting System Standards”, version 1.0 from 2005 and version 2.0 from 2021, say this:
1.1.6-I – Ignore extraneous marks inside voting targets. The voting system must include a capability to recognize any imperfections in the ballot stock, folds, and similar insignificant marks appearing inside the voting targets and not record them as votes.
But Windham, New Hampshire bought its AccuVote OS machines in 1998, so let’s look at the 1990 Federal Election Commission standards:
Reading Accuracy: This … Subsystem attribute refers to the inherent capability of the read heads to … discriminate between valid … marks and extraneous perforations, smudges, and folds.
Although New Hampshire does not consider itself bound by these “voluntary” standards, certainly the AccuVote OS was sold in states that asked for test reports against those 1990 standards. So presumably the AccuVote OS, when new and when properly calibrated, was supposed to ignore fold lines. However, it appears testing agencies don’t actually test for this, even if the standards call for it.
It is not clear whether these machines have been recalibrated to different settings than the manufacturer preset–sometimes there are reasons for doing that. And the careful testing by the New Hampshire audit team makes it clear that the AccuVote OS does not always ignore fold lines.
Fold lines through vote targets
Even though voting machines are not supposed to interpret creases as votes, experienced election administrators know that they should keep the fold lines away from the vote targets (ovals that the voter fills in).
Most ballots are printed by private companies that contract with local election officials. In western states, where many millions of voters routinely vote by mail, election administrators contract with their printers not only to print the ballots, but to fold them and insert them in envelopes as well, and often also to bulk-mail them directly to the voters. Those printing companies get trained (either by the election officials, or by the major voting machine companies) about how to set up their high-speed automatic equipment to fold the ballots, avoiding vote targets.
But in some eastern states where there have been relatively few absentee ballots, local election officials often mail out the ballots themselves. In 2020, as in previous years, the State of New Hampshire contracted with a printing company to print their ballots. The printer printed the absentee ballots with score lines, that is, indentations in the paper that show where it should be folded–so when you fold by hand, it ought to fold at the scores. And indeed, these score lines were indented in the right place, avoiding the vote targets. If only the ballots had been folded at the score lines, there would have been no problem.
Jennifer Morrell, who was a local election official in Utah and Colorado, writes,
We always worked with our mail ballot printing vendor to ensure the pre-scored fold lines did not hit a target area on the ballot. It was a bit tedious because we had 600+ ballot styles but I don’t recall it ever being a problem.
My recollection is that they were always able to find a single position for each fold mark (generally just two folds so the ballot was folded in thirds) that worked with all styles. One year was challenging because our ballot was so long we had three fold marks (ballot folded in half and then in half again) which put one of them squarely in the middle of the ballot.
For flat ballots voted in-person at polling locations, we printed those “on demand” and purchased pre-scored ballot stock from the vendor (with the folds in the same position as they were on the mail ballots). This mitigated (but not alleviated completely) the risk of voters folding the ballots in a way that would create a problem. Mainly, if they folded a ballot that was not scored, there was a potential for the fold to damage the timing mark causing the ballot to be rejected by the scanning equipment as unreadable. Which then means it would need to be sent for duplication/remake.
In previous years, there weren’t many absentee ballots to be mailed out, so Windham employees would fold the (prescored) ballots by hand, put them in envelopes, and mail them. Likely enough, the creases would usually be on the score lines, avoiding the vote targets. But in 2020, during the pandemic, thousands of voters requested absentee ballots. The town improvised: they used a folder/inserter machine (normally used for DMV notices) to fold the ballots; then they “ironed” the folds with a coin or scissors-handle to make them fit in their envelopes.
This machine is probably wonderful for its intended purpose–folding business letters, electricity bills, DMV notices, etc. before mailing to customers. But it does not put creases in exactly the right places for ballots; either because it had not been adjusted for that, or because it does not put creases straight across (they’re slightly diagonal), or because even when adjusted it doesn’t always put the crease in exactly the same place.
In particular, the absentee ballots folded by the DS-35 were not folded at the score lines; many of them were folded through the vote target for Democratic candidate Kristi St. Laurent.
Dust and calibration
The fold line went through a vote target–but isn’t the voting machine supposed to ignore that? In principle, yes. But these creases are substantial ridges! Windham was using four AccuVote optical scanners on November 3rd, and the auditors found that some of these machines were much more likely than others to interpret folds as votes. The auditors also found that there was a substantial build-up of dust on the read heads of the scanners; and that these read heads were enclosed in such a way that it would be difficult to get in there and clean them, or even to notice that there was a dust build-up. And they found “dust is a major contributor to reading errors of folds;” cleaning out the dust reduced the error rate.
One can imagine different hypotheses for why dust could increase the sensitivity to fold marks. Perhaps dust on the read head blurs the image, making the fold appear wider. Perhaps dust reduces sensitivity overall, so that as dust built up over the years the technicians recalibrated the machine to increase its sensitivity (so that legitimate votes were not missed).
Could this be happening elsewhere?
Should we be worried that election results are wrong in other jurisdictions that use AccuVote optical scanners–or any kind of optical scanners? Let’s see what chain of circumstances caused this problem:
- Ballots were folded improperly, in part because the COVID-19 pandemic caused a last-minute surge in absentee voters and the town had an unforeseen need to fold 3000 ballots. (In other times and places, jurisdictions that mail out thousands of folded ballots usually have them folded by printing companies that are experienced in the special requirements for ballots.)
- The fold line, as produced by the automatic folding machine, happened to fall upon a vote target.
- The AccuVote scanners had not been cleaned of a (perhaps years-long) dust buildup. Do election administrators in other places clean the read heads of their optical scanners? Are other models of voting machine susceptible to this problem?
- Windham had disabled overvote notification on these scanners (following State policy). That is, reading the fold as a vote caused (in hundreds of cases) more votes to be cast in this contest than allowed, so the machine noticed an overvote and didn’t count any of the votes in that contest (on that ballot). If the machine were set to reject overvoted ballots on the spot, in the presence of the voter, that gives the voter a chance to get a fresh ballot and try again. You might think that doesn’t seem apply to absentee ballots; but in fact it can: there was a poll worker feeding those absentee ballots through the scanner, and overvote rejection would give the poll worker a chance to place overvoted ballots into a separate pile for hand counting. It’s a best practice, followed in many other jurisdictions, that all overvoted ballots are segregated for manual interpretation.
- Windham had ignored overvote reporting. At the close of the polls, the AccuVote OS prints out a cash-register tape with results. The overvotes are reported as BLANKS (which also includes ballots in which the voter didn’t vote at all in this contest). It would have been better if the voting machine reported OVERVOTES separately from true BLANKS. But even so, the extremely high number of blanks could have been a warning sign to investigate further, by a hand recount (without waiting for a candidate to request it)–except that such a recount would not have been legal under State law.
- New Hampshire does not have Risk-Limiting Audits. An RLA examines a random sample of the paper ballots, sampling just enough ballots to ensure that the outcome claimed by the voting machine is the same as you’d get by recounting the paper ballots by hand. One motivation of RLAs is to catch hacking, but they work just as well to catch any kind of systematic error. If New Hampshire had RLAs, then any problem like this that could have changed the outcome of an election would probably have been detected–and corrected by a recount.
Could folds have changed votes elsewhere in New Hampshire? Possibly. Did other towns use nonstandard equipment to fold their absentee ballots? The town clerks might know. And if so, which vote target (if any) would the fold line have fallen upon? Unknown. Do other towns have AccuVote OS machines that have not been cleaned for 22 years? Probably. Do other towns disable overvote rejection? Almost certainly. Do other towns ignore high numbers of BLANKS on results printouts? Probably. Do other towns do Risk-Limiting Audits that would have caught this? No, state law prohibits that.
Recommendations
Optical-scan voting can be extremely accurate when best practices are followed. New Hampshire should adopt these practices immediately:
- Enable overvote rejection on the AccuVote OS. That means, the voting machine returns the overvoted ballot to the voter or pollworker for correction. When the voter is not present (as for an absentee ballot) the overvoted ballot should be segregated for manual counting, because often a human can readily determine the voter’s intent. When the voter is present, the voter can be given the choice of either voiding their ballot and casting a new one, or having their ballot segregated for manual counting.
- Clean the read heads of all their optical-scan voting machines as often as necessary, which might be every year or every four years, to be determined. This will require some disassembly of the machines.
- Set the voting machines to report (in each contest) the number of overvotes separately from the number of blanks. In principle there should be few reported overvotes if recommendation #1 is followed. Even so: if the number of overvotes is more than half the margin of victory in any race, examine all overvoted ballots; or if overvoted ballots cannot be segregated, recount the whole contest.
- Have absentee ballots folded automatically by the election-services contractor, rather than folded ad-hoc in town offices. Town Clerks should inspect a sample of absentee ballots before they are mailed to make sure the folds avoid all vote targets. If absentee ballots are mailed directly to voters by the services company, then Town Clerks should inspect a sample of the returned absentee ballots to make sure the folds are in the right place. (If not, count those ballots by hand.)
- Determine whether the procedures and software used for the layout of optical-scan ballots properly keep all vote targets away from any portion of the paper where folds might be made. (See “lesson” below.)
- Adopt Risk-Limiting Audits statewide. All the recommendations 1-5 above are reactive to the specific unforeseen problem that occurred last time. But what different problem will come up next time? The purpose of mandatory, every-election RLAs is to detect any kind of problem that might cause machine-reported results to be different from what you’d get in a correct manual recount. And these mandatory RLAs should be done before results are certified, so that if the RLA does detect a problem, then it can be immediately corrected by a recount. And one thing we learned from this is that the Secretary of State’s office can do recounts accurately.
Lessons for voting machine design
Humans have no difficulty understanding that a fold line is not a vote; we don’t look only within the oval, but at a more holistic context. One might think that modern algorithms, running on the more powerful CPUs that voting-machine makers put in their contemporary products, might interpret marks much more accurately than the AccuVote OS from the 1990s. I haven’t seen any evidence of this, one way or the other. It might be worth subjecting newer products to independent testing; or doing research on vote-mark recognition algorithms, or both.
Furthermore, there are good standards for the design of ballots so that voters are less likely to make mistakes: Effective Designs for the Administration of Federal Elections, Section 3: Optical scan ballots. But that guide says nothing about absentee ballots; the only instructions it gives are “do not fold the ballot”, which is not useful advice for mail-in ballots. Updated design guidelines would be useful, saying vote targets shoud not be placed anywhere near the point in the paper were the fold will most naturally go.
Ballot-layout software should be improved to take fold-line positions into account when placing vote targets. As it is now, it seems that the targets go where they go, and then the election administrator and printing company have to scramble to find a place where the fold can go.
Finally, even though the Federal standards require optical-scan voting machines to ignore fold marks, it appears that this is not tested in the “certification test plan” for a voting machine like the AccuVote OS. If the standards say that voting machine should ignore folds, then that should be tested for.
Dr. Appel,
As a NH voter who has been paying attention to our elections since early 2008 (when I first learned we were using the then Diebold Accuvote in my town and state), I agree with many of your recommendations above.
I’ve been working with legislators and a former town moderator for a way to check the count ON ELECTION NIGHT. I’m including the BEST idea I’ve heard (believe you met the late Danville moderator Wally Fries when you testified to a state advisory committee in 2008 or 2009.) The SoS stopped this practice in Sept. 2016 and in four tries, the NH legislature hasn’t yet corrected this mistake. Our last effort, SB 79, which gives guidance to larger jurisdictions that use more than one computer, was supported by many voters but opposed by the SoS was retained by the Senate and is linked here:
http://www.gencourt.state.nh.us/lsr_search/billText.aspx?id=999&type=3
Legislators and many local election officials would prefer that the Secretary of State would conduct any post-election audit. That brings up ballot chain of custody issues AND the fact that our NH Constitution and laws consistent with it make local officials AND the public locally responsible for making sure reported results are legitimate and as accurate as possible on election night.
Could an RLA work at the local level on election night? If so, would it be checking ALL races or just those within a certain winning margin? One of NH’s problems is that currently local officials have ONLY 48 hours to report results to the SoS and candidates only have until the Friday after the election to request recounts.
I’d like your permission to share any response with current legislative election law committees and two legislators who filed a post-election audit bill that was retained for more work this summer. Thank you.
Here’s the BEST idea I’ve heard but would be willing to consider a locally-based election night RLA if you can convince me that would be BETTER.
Parallel Hand Counts—Example of New Hampshire Common Sense
Former Danville moderator Wally Fries always oversaw hand counting of 1-3 contests/ballot questions on election night to ensure an accurate computer count.
Why:
1. had worked with computers for years and knew there could be breakdowns and their reliability needed to be checked. As a member of several state advisory groups he also knew the pre-election ballot testing wasn’t enough. The hand count check made it more likely any error would be detected and accurate results would be reported to Concord (as NH Constitution and state law require).
2. knew there had been reported instances of tampering and wanted to discourage any possibility of that happening in his town’s elections.
3. wanted the public to have confidence in his town’s election results.
How:
1. Selective sampling—he chose contests based on a) expected closeness
b) vulnerability to tampering c) importance. (For example, he would hand count just the competitive races in Presidential Primaries. and reconcile the “other” piles with total ballots cast and number of voters.) UNH statistician confirmed the validity of this kind of sampling.
2. Double count hand count using “sort and stack method.” (Election officials sort into piles, first counter cross stacks 25 ballots at a time, second counter verifies count or team determines voter intent, reconciles discrepancy). Public could observe.
3. Verified hand count checked with computer total. Reconcile any differences.
If Wally believed three races might be close, he’d check all three. Recounts cost money, he reasoned and at least candidates would know that one jurisdiction had an accurate count.
Cost: No additional cost for town or state
I would like to know why the NH state authorities have been dragging their feet in the effort to correct these systemic voting machinery malfunctions. This is important enough for me to volunteer my services to clean & maintain machines. I have the skill set, I’m retired and willing to submit to whatever anti-bias testing would be required. There must be a thousand others in the state of New Hampshire like myself.
What is a person to think? Are these authorities involved in some kind of malfeasance? Why does the SoS resist any movement to resolve these obvious issues so categorically? Its bad enough that our state is gerrymandered to hell.
This past legislative session in NH, there was a second attempt to codify the HAVA overvote notification requirement AND bring NH into compliance with both federal AND state election laws (where voter intent is the legal standard for counting our votes). HB 491 was opposed by the Secretary of State, all 11 Republican members of the House Election Law Committee, the Republican House Majority office and the town and city and city clerks association. The Derry Town Clerk (see my previous post above re: the alarmingly high overvoted ballot rate in Derry) was part of the clerks’ legislative committee recommending opposition to the bill.
http://www.gencourt.state.nh.us/lsr_search/billText.aspx?id=796&type=4
It wasn’t voted on by the entire House this session but the bill’s sponsor, who intended to file an amendment to include ALL elections, not just federal ones, is planning to bring the bill back next year….maybe the auditors will make this recommendation directly to state officials and they will choose to support this legislation OR the Ballot Law Commission can simply require it as a rule for computer systems.
We tried to pass a similar bill in 2018. The SoS, all members of the House Election Law Committee and the Republican House Majority Office opposed the bill.
The Secretary of State’s opposition in 2018 was because he said some people WANT to vote for more than the allowable number of candidates, which, of course, they could still do IF they were notified of a computer-read overvote. This year, he claimed NH was treating all voters the same. Since voters in hand count towns didn’t have a chance to correct an over vote, neither should voters using the computer. Our small sample of 3 towns, one city and 2 city wards using the AccuVote showed an average overvoted ballot rate of 2.7%. Our one hand count town had a total of 3 overvotes. If they were on SEPARATE ballots that would have been.19% in that town. (1,602 ballots cast)
Anyone interested in the legislative history of HB 1486 in 2018 (my testimony is included) can view it here:
http://gencourt.state.nh.us/SofS_Archives/2018/house/HB1486H.pdf
To your question, was this an issue in OTHER NH communities?
Here is the request from three citizens on Dec. 3, 2020 to ask for the AG to investigate the high number of over-voted ballots (4.7%) in Derry (a neighboring town to Windham), and absentee ballots statewide. The computer counting ONLY absentee ballots in Derry showed a 14.2% over voted ballot rate. The AG confirmed he had received this request and took no action on it. We attached a spreadsheet that showed the overvoted ballot rate for each of the 8 computers used. Believe Derry is the LARGEST single voting jurisdiction in the state, with 18,100 ballots cast in November 2020
December 2, 2020 (sent by regular mail, emailed Dec. 3)
Gordon J. MacDonald, Attorney General
NH Department of Justice
33 Capitol St.
Concord, NH 03301
Re: Request for Investigation, high overvoted ballot rate in Derry/absentee ballots statewide
Dear Mr. MacDonald,
1) We ask you to use your authority under RSA 656:42 IV to investigate an alarmingly high overvoted ballot rate in Derry for the November 2020 election. Derry reported a total of 6,428 absentee ballots of 18,100 ballots cast. Some would be overseas ballots and others tallied by hand.
Enclosed is information from the eight computers used. Computer one tabulated ONLY absentee ballots (572 over voted ballots, 14.2%); other absentee ballots were counted by other computers, with a 4.7% overvoted ballot rate when totals are combined (848 ballots). Computer 5 also showed a high overvoted ballot rate, 5.8%.
You should be able to confirm the numbers with the town clerk.
In November 2018, Derry mostly tallied its absentee ballots on one computer, with an estimated 5% overvoted ballot rate for that computer.
2) Are absentee ballots statewide showing a significantly higher voter disenfranchisement rate than election-day ballots?
3) If so, why? What are your recommendations for decreasing these numbers?
As we told you in September 2017, folds in absentee ballots may be misread as overvotes, there are many instances of computers misreading valid votes as overvotes and there are fraud possibilities. One can be targeted to absentee ballots where the voter’s party affiliation is known.
Since then, we have been doing some checks of overvoted ballots in various towns, but prior to this discovery, the highest was 2.5% in Jaffrey in the Nov. 2012 election.
NH doesn’t require reporting of overvotes and neither law nor the SoS requires local officials to print that information for the general election. (Only 2 of Nashua’s 9 wards had the requested overvote information available, 143 overvoted ballots of 10,702, 1.3%). It is impossible to know why or how many NH voters are being disenfranchised compared with other states or if certain races are impacted more.
Both Vermont and Massachusetts program their computers to notify election-day voters of a computer-read overvote or completely blank ballot so they can choose to request a replacement ballot and have their votes counted. NH doesn’t.
VT reports overvotes for each contest and each locality, as you can see here.
https://sos.vermont.gov/media/heqnbco5/generalofficialresults.pdf
Overvote rate for President on election night was 278 of 370,968 ballots cast, .075%.
MA has recently completed its 3% post-election audit and found a total of 7 overvotes for all races counted on election night (100,349 ballots/over vote rate of .007%). Additional overvotes found in the audit (68 total for ALL races) were mostly attributed to 73 ballots not counted on election night.
https://www.sec.state.ma.us/ele/elepostelection/postelectionidx.htm
https://www.sec.state.ma.us/ele/elepostelection/2020-Audit-Report-Narrative.pdf
In NH, we are finding overvoted ballot rates almost always exceed 1%. Ballots may contain more than one error, thus disenfranchising voters for more than a single contest.
All three states had more absentee ballots this past election, but we see significant overvote voter disenfranchisement only in NH.
We ask that any review of Derry ballots be a transparent, public process and that your findings include recommendations to policy makers, election officials and or the Ballot Law Commission, which makes rules for the use of computers in NH. RSA 659:64 requires that NH enfranchises as many voters as possible. Appeal of McDonough, 149 N.H.105, 112 (2003).
Thank you. Please let us know if you have any questions.
Copies: Derry Town Moderator, Ballot Law Commission, ACLU-NH, DOJ attorneys-Anne Edwards, Jane Young, Nicholas Chong Yen
Yes, New Hampshire’s hand recounts of the paper ballots are considered exemplary, yet SoS Gardner is interested in audits of scanned ballot images in the future, as evidenced by SB 283 in 2019 and SB 89 in 2021, which establishes a committee to study post election audit counting devices/scanners. Happily, there is some popular sentiment in favor of hand-counted audits of original paper ballots. I’ve been citing the 2017 Kobach commission testimony by you, Ron Rivest, and Harri Hursti. Hoping you haven’t softened your stance since then?
Sorry, I see that you co-authored this paper that should answer my question: https://georgetownlawtechreview.org/wp-content/uploads/2020/07/4.2-p523-541-Appel-Stark.pdf
P. 537
Audit the Digital Images?
Some vendors are promoting systems that create digital images of ballots. These vendors claim that the images make RLAs easier to perform because fewer (or no) paper ballots need to be inspected. That is incorrect: if a risk-limiting audit relies on images of ballots, it must check that the error in making the images from the voter-verified paper ballots plus the error the system made interpreting those images to make cast-vote records is not large enough to cause the electoral outcome to be wrong. It is a mathematical fact that this requires examining at least as many physical ballots as an audit that compares CVRs to a human reading of the paper ballots, without relying on the digital images.
Dr. Appel:
Since cast-vote records is not a term that is familiar to most voters, would this next sentence be an accurate rendering of your meaning in the last sentence above? A risk-limiting audit that relies on digital images of ballots requires examining at least as many corresponding paper ballots as a hand-counted audit of the paper ballots alone.
8 million people disagree with you.
Did you even read the report?
Trump won
An apparently similar failure with a similar Accuvote device caused a miscount in a 2005 Eagle County Colorado Home Rule Charter Commission Election that contained several vote for three contests. I was a candidate in the election.
In that election it probably wasn’t a fold crossing a target that caused the miscount but it was a miscount caused by a properly positioned fold.
The Accuvote in CO was set to reject upon detection of overvote, unlike in NH. The instruction to the in-person election judges upon rejection was to offer the voter a chance to check and correct the ballot and if the voter is satisfied with the marks to use an override button to disable the rejection function. Otherwise the voter could remake the ballot. Within central count a similar instruction meant the election judge would check if there was an intended overvote and decide whether or not to insert the ballot with the override activated.
In the 2005 election, thousands of ballots had already been centrally tabulated on the Accuvote by the time a few too many overvote rejections were noticed among the absentee ballots. The extra rejections caused election judges to study the paper but in most cases no overvote was seen. At some point it was decided that there was a technical problem. A machine tabulation was compared to a hand count and a 5% discrepancy was found. At that point a hand count replaced the faulty machine count before certification.
Ironically the LAT ( pre-election test) couldn’t have detected the error as the test was not conducted on folded and mailed ballot packets. The RLA hadn’t been invented. The election was very low key and few of the vote for three were fully voted. Extraneous marks could easily add votes without causing an overvote. Ghost votes would have been noticed in a very good tabulation audit and were avoided in a full hand tally.
Diebold who had manufactured the ballots for the election and serviced the machines was asked to research and explain. They eventually concluded that the toner had been inadequately bonded to paper( by Diebold). A thick black bar located on the inside of a fold that only after folding rested next to one set of contest targets was responsible for depositing particles of toner into one or more candidate targets. The deposition was thought to be occuring only after the compression that occurs when folded ballots were mailed.
The moral of my story is parallel to the conclusions above. There are probably more than one already discovered physical anomalies that affect the paper plus Accuvote system. While it is true that NH uses a printing press and not a Xerographic technique for printing most ballots, it is wise to assume that various unexpected undiscovered causes of discrepancies still exist and ought to be caught by a more thorough Logic and Accuracy Test and if not at that point, then during a well executed Risk Limiting Audit that escalates into a full hand tally that determines the outcome.
In response to the above events, the Clerk and Recorder of Eagle County allowed me to conduct research on the Accuvote devices involving repeated test elections. I tabulated many very small elections using repeated insertions of test marked ballots such as 10 insertions of each. I discovered that overvote detection and overvote adjudication of the two Accuvote devices I tested suffered from unexpected anomalies. It was uncertain if a clearly voter overvoted contest would be adjudicated as overvote or as a vote for the larger mark. After 10 insertions I might see 6 or 8 votes instead of 10.
I showed this to the clerk and that led to the purchase of Hart Ballot now I have referred to elsewhere.
I concluded that when using Accuvote in the stand alone configuration it is wise to hand check for possible overvote conditions that might be misinterpreted. It seems always best to use overvote rejection and never the override function. The LAT must be as close to election conditions as possible. And a RLA well implemented on all contested contests will take care of remaining tabulation error. Unfortunately the Accuvote does not create either a ballot image or a cast vote record. So the RLA cannot be as efficient as when those are available.
Then what remains for outcome validation is to be sure the tabulated ballots represent legal votes on eligible contests and all legally cast votes are included. Ideally elections will someday have audits in place to confirm all that. Sometimes these are called compliance audits but I prefer to label them registration, eligibility and chain of custody audits.