<x-flowed>I've posted a draft paper of mine on the design of current VVPAT systems here:

Design and the Support of Transparency in VVPAT Systems in the US
Voting Systems Market
<http://josephhall.org/tmp/jlh-vvpat-design-transparency.pdf>

An updated version of this paper will be published later this year by
the AEI-Brookings election reform project (I'm still looking for a
peer-reviewed venue (and possibly a collaborator interested in
extending the analysis.)

I'll intersperse some comments below:

On 8/2/06, Daniel Tokaji <tokaji.1@osu.edu> wrote:

The Diebold TSx and ES&S iVotronic VVPAT systems do print the voter's
choices behind a transparent window, so the voter can see but not touch it,
and I think Sequoia's AVC Edge with printer does the same. They don't "cut[]
off the paper" and let it float down into a bin.  Instead, they print onto a
reel-to-reel (or, as some have referred to it, "toilet paper") style paper
tape  This creates a privacy issue, since it's at least theoretically
possible to trace back individual voters' choices, if you know the order in
which they voted on a particular machine.

All the VVPAT designs of the four major vendors (DESI, ES&S, Sequoia,
Hart InterCivic) do the behind-glass reel-to-reel implementation of
VVPAT.  Avante (who is suing three of these four for patent
infringement) makes a DRE+VVPAT system that does do exactly what Mark
Scarberry suggests: it displays the VVPAT under glass and then if the
voter approves, it cuts the paper record and allows it to drop into an
attached ballot box (if the voter doesn't approve, the paper record is
marked as spoiled, cut and dropped in a separate receptacle for
spoiled or voided paper records).  There is also a newer vendor,
Precise Voting, that seems to do a cut-sheet DRE+VVPAT that also saves
an audio file of what people with visual disabilities hear as the
read-out of the contents of the paper record:
http://www.precisevoting.com/ (unfortunately, I haven't had the
opportunity to learn more about this system or play with it yet.)

Why vendors haven't developed a model that cuts off each individual ballot
is something I don't know, but I suspect there may be some mechanical
difficulties in making such a system work properly.   The complexity of
existing DRE-with-VVPAT systems already creates some problems, as I've
described here and here, not the least of which have to do with verifying
and auditing votes.  Incorporating another moving part with receptacle would
make the machine more cumbersome and add to list of things that can go
wrong, thus adding to the costs of purchasing, maintaining, and storing such
a system.  That's not to say it can't be done but, to my knowledge, it
hasn't been done yet Ð probably because there hasn't, as far as I'm aware,
been much demand for it.

Dan's criticism is valid, in my opinion, and my paper lays out a
number of other areas of critique for these designs.  Another common
criticism is that these systems use thermal paper (like what is loaded
in a cash register receipt printer).  This paper is flimsy, easily
damaged in harsh environments and curls so it is hard for manual
recount operations.  I expect to see the major vendors start to
compete on better designs of VVPAT enabled systems now that their are
28 states that use them in whole or in part... I think we'll see more
cut-sheet designs and paper records printed on higher paper-weight
paper that isn't as fragile.

(Note that most of the current systems that are being purchased as
being HAVA-compliant will not necessarily pass the certification
tesitng required in late 2007 to meet the 2005 Voluntary Voting System
Guidelines... so Vendors will either upgrade their systems to meet
these standards or, hopefully, design systems that are more modular
such that pieces can be swapped out to meet the rapidly changing
standards (this is similar to the case with avionics components).  The
federal standards are required by some 40 states now and will be
updated more frequently than they have been in the past, as any
standard for computerized machinery should be.  It still remains to be
seen that funding this turnover in equipment is possible at the state
or federal level.)

I'll shut up now... best, Joe