Most voting systems used in federal, state, and local elections in the United States rely on computers in some way. The most computerized is the direct recording electronic voting machine, in which votes are recorded directly onto computer memory devices. DREs are the most technologically advanced of current voting systems. They and other forms of electronic voting offer substantial promise for improving elections for both voters and election officials. Questions about the security and reliability of DREs were a relatively minor issue until 2003. Two factors led to a sharp increase in public concerns about them: (1) the Help America Vote Act of 2002 (HAVA) requires at least one voting machine in each precinct to fully accommodate disabled voters and DREs are the only system that currently meets this requirement; and (2) the security vulnerabilities of DREs were widely publicized as the result of several studies released in 2003. Much of the debate over DREs has focused on whether they should be required to produce a paper ballot that can be verified by the voter as a solution to potential vulnerabilities. This approach is often called the voter-verified paper audit trail (VVPAT). Bills to require VVPAT were introduced in the 108 th and 109 th Congresses, but there is divided opinion about both VVPAT and the security vulnerabilities of DREs, particularly with respect to the comparative vulnerabilities of other voting methods and various other aspects of election administration. Proposals to require that DREs use VVPAT or another method of verification have been seen by some observers, including many computer-security experts, as the method of choice for addressing the concerns. However, others, including many election officials, believe that VVPAT is unnecessary or even counterproductive and that security issues are best addressed through other approaches. The public debate about DREs and VVPAT has led to some confusion about the problems and issues involved, and as a consequence, the options that might resolve them. The questions and answers that follow address selected issues and misperceptions concerning DREs and VVPAT, in an effort to clarify and inform the ongoing policy discussion. Questions that arise frequently with respect to the controversy surrounding DREs and possible misperceptions in the debate can be classified into three categories: those relating to DREs themselves, those that relate to paper audit trails, and those that relate to recounts and audits. Questions in each of those categories are addressed in turn below. Voters in various jurisdictions across the country experienced difficulties with the voting process in the November 2004 election, and to some extent in 2006, but problems with DREs were a comparatively minor issue on the whole. Both during and after the elections, the media reported issues with voter registration, the rules for counting provisional ballots, the length of time required to vote, absentee ballot problems, and allegations of voter intimidation and fraud, along with reports about malfunctions of voting equipment, including DREs. A number of malfunctions relating to DREs were covered prominently in media reports on election problems, particularly problems in Franklin County, Ohio, and Carteret County, North Carolina (discussed in greater detail below), in 2004, and Sarasota County, Florida, in 2006. Various glitches and procedural problems were reported with DREs in other states as well, but machine malfunctions that could not be attributed to human error were the exception in 2004 according to a compilation of media reports by the Election Reform Information Project. Two significant problems were reported in 2006. One was "vote flipping" on touchscreen machines, in which a voter reports that the DRE displayed a different choice (usually adjacent on the screen) from the one the voter intended. This problem could be caused by inaccurate touching of the screen by the voter, or by miscalibration of the screen. A potentially more serious problem was an apparent discrepancy in ballot totals in the race for the House seat in Florida's 13 th congressional district, where the apparent undervote in the Sarasota County part of the district was several times that in parts of the district in other counties. However, the most likely explanation for the high undervote appears to be faulty ballot design, not a hardware or software problem with the DREs. In comparison, many problems have been associated with provisional and absentee ballots. A survey sponsored by the federal Election Assistance Commission (EAC) and performed by Election Data Services found that in 2004 at least 1.9 million voters cast provisional ballots nationwide, which were counted or not according to different rules in the various states. In Ohio, which required that a provisional ballot be cast in the voter's home precinct, approximately 22% of the 157,714 provisional ballots cast in the state were not counted (nearly 34,000 ballots). The percentage of provisional ballots counted by states ranged from 0% (Idaho) to 100% (Maine), with an average of about 50%. With respect to military and overseas voters, a survey of 761 local election officials by the National Defense Committee, a private organization, reported that 126,952 absentee ballots were mailed to members of the military and citizens living abroad in 2004, and 94,359 were returned and counted in 2004. More than 30,000 of the absentee ballots in this survey (approximately 26%) were not returned at all, were disqualified for procedural reasons, or were returned too late to be counted. Long lines also plagued voters in many states in 2004, with some waiting hours to cast a ballot (one Ohio voter reportedly waited 10 hours to vote). While it is impossible to know how many voters abandoned lines without voting, long lines impede the voting process and create a final obstacle at the polling place for those who turn out to vote. In 2006, problems with voter registration and polling-place administration were more commonly reported. Among other sources, the Election Incident Reporting System, affiliated with the Verified Voting Foundation, a VVPAT advocate, recorded 42,841 complaints about the 2004 election, 11% of them relating in whole or part to voting machines. Most of the complaints in that data set related to registration or polling place problems. The major alternative voting system to DREs is optical scan, which uses paper ballots, usually marked by hand, that are read electronically. In 2006 almost half of voters used optical scan, and 40% used DREs. While technologically far simpler than DREs, optical scan systems are not immune from problems, and many of the difficulties reported in 2004 and 2006 were for these systems. However, media reports and statements by activists and others sometimes do not distinguish between the two types, lumping them together as "electronic voting systems." To the extent that voters, in contrast, reserve this term for DREs, public confusion and misunderstanding about the source of voting-system problems can result. In addition, if such reports and statements fail to distinguish between procedural and technological problems, mishaps that result from human error may be erroneously regarded as problems with the technology. DREs have been tested by scientists, but the systems have not generally undergone the kind of open scientific scrutiny that might be expected. They are proprietary machines, and manufacturers require confidentiality agreements of those who wish to acquire them. Testing is done as part of federal and state certification processes, but detailed results are not publicly available at present. More detail has been provided in only a relatively few cases, such as the analysis of software obtained from a manufacturer's unsecured website in 2003, subsequent studies by the states of California, Maryland, and Ohio, and a few independent reports. Most of those studies focused on DREs made by Diebold, one of several manufacturers of these systems. HAVA has established some procedures, including the formal involvement of the National Institute of Standards and Technology (NIST) and the science and technology communities, in the standards-development and certification processes (§214 and §221). These and other factors may lead to an increase in the involvement of scientists in the study of DREs and other aspects of election administration. That has already happened to some extent, with, for example, the establishment of the Voting Technology Project by the California Institute of Technology and the Massachusetts Institute of Technology, the involvement of the American Association for the Advancement of Science (AAAS) and the National Research Council in election reform issues, and the awarding of a major grant by the National Science Foundation to several institutions to establish a center for voting technology research. DREs currently in use have a unique set of security vulnerabilities, which has been demonstrated by several of the studies cited above (See footnote 12 ). It results from the same feature—reliance on a computer for casting and recording of votes in a single machine—that gives DREs their capabilities in accessibility, usability, and efficiency. Because the machines rely on complicated software, it is at least theoretically possible that someone could insert hidden computer code that would add, subtract, or change votes. There are several things that such malicious code, or malware, might do. In the best known potential exploit, the hidden code would cause the DRE to record a different vote from what the voter sees on the face of the machine. Another possibility is that the malware could change vote totals after they had been recorded but before they are downloaded for tallying. While an optical scan or punchcard counter could also be programmed to record a different vote from that intended by the voter, with those systems the ballot that the voter saw is preserved as part of normal practice and can be checked independently by another machine or a human. That is not possible with a DRE, where the choices the voter sees on the face of the machine are ephemeral—they are reset when the voter casts the ballot. The actual record of the voter, preserved on an electronic medium, is not something the voter ever sees. In that way, DREs are like lever machine voting systems, in which casting a ballot advances mechanical counters, which the voter cannot see, and resets the levers for the next voter.