Treating dichotomous data as metric data

[sahrens2000]

Dear all,

please forgive me if this has been asked many times before, but I
couldn't find any other info about it. BTW, is there a FAQ section?

My problem is this:
In market research we deal with many data that are batteries of
questionnaire items but where the items are coded as dichotomous
variables (e.g., 1 for "applies", 0 for "doesn't apply"). From time to
time I hear that it is possible to treat dichotomous variables as
metric variables which would allow me to make use of Pearson
correlation coefficients or even run PCA or Factor Analysis on such
data. However, I haven't found more detailed information on this.

Thus, my question(s):
(1) Is it indeed possible to treat dichotomous variables in the same
way as metric variables? I know that there are probably special
techniques in factor analysis and/or correlation (tetrachoric), but I'd
rather like to know if I can use the standard techniques without too
much loss of interpretability (so that I can use standard stats
packages).
(2) Can you point me to any references (books, articles) where this
issue is addressed?

Any comments/input would be truly appreciated.

Thanks in advance,

Stefan Ahrens
IVE Research International,
Hamburg, Germany


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Re: distribution of daily low/high

[Li0N_iN_0iL]

Herman Rubin wrote:

>The Brownian motion here is one-dimensional.

See chapter 17 (Brownian Motion of a galvanometer), 
"Thermodynamics", Francis Weston Sears (Addison-Wesley).


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Re: NY Times on "statisticians' view" of election

[mal11]

In article <[EMAIL PROTECTED]>,
  Rodney Sparapani <[EMAIL PROTECTED]> wrote:
> 2) they didn't examine the undervotes in the original count or the
state-law mandated
> re-count; it's only in the third count where they are considering
them, which is what
> is so disturbing.
>

i tell you want I find disturbing:
the "chad undercount error" that was discovered in the Volusia
county complete hand count went 62% to Gore and 38% to Bush.
However, as a whole, Volusia was only 53% Gore and 45% Bush.
Since when do chads play favorites, or is this entirely realistic
is one were to model chad failure as a Poisson process?

mlewis
ut southwestern medical center at dallas


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Re: Fwd: Butterfly ballots (fwd)

[Eric Bohlman]

Ronald Bloom <[EMAIL PROTECTED]> wrote:
>  Would the group  of kids doing a post-hoc experiment be
> biased inasmuch as the nature of the problem at hand may
> have become common-knowledge by now; even among kids; and
> so one would be forewarned of the error-mode in question,
> and be much less likely to fall into that mode of error?

Quite likely.

> At any rate, what inference am I being prompted to draw here? 
> That the people who claimed to have been confused were
> either (a) ignoramuses or (b) changing their tune after
> the fact?

> Is there some more generous interpretation, (c), say?

I suspect the average visual acuity of the fourth-graders was better than
that of the Palm Beach voters.

There are certain cognitive tasks that children do better on than
adults; could this be one of them?  Or could it be one of those tasks that
younger adults do better on than older ones?  Valid research questions
here, and if the latter turns out to be true, it would certainly have
legal implications for future ballots.

Did the exercise actually involve punching a hole using the apparatus
found in an actual voting booth, or did it involve filling in a
circle?  If, as I suspect, it was the latter, than I doubt the results are
transferrable.  There are plenty of user interfaces that seem to work in
mockups, but fail in production because of seemingly minor differences
(one of my pet examples is that a simulated thumbwheel control as often
seen on MP3 player software or other programs with a "skin" interface
requires an entirely different set of motor movements (and skills) than a
real-life thumbwheel; to me at least, the motor movements involved in
operating a simulated thumbwheel rather close resemble those involved in
removing a child-resistant cap from a medicine bottle ("press and turn
simultaneously")).



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Re: 3 cheers for a pilot!

[Gary Winkel]

Hi Dennis!

I was wondering when someone would have enough sense to suggest the need
for a simple pilot study.  Thank you for your good sense and good advice.
 It is amazing how much time, energy, and effort is saved by taking such
a simple step as running a pilot.

Thank you,

Gary Winkel
Psychology
City University of New York

On Tue, 14 Nov 2000 18:19:15 -0500 dennis roberts <[EMAIL PROTECTED]> writes:
> At 02:18 PM 11/14/00 -0600, Simon, Steve, PhD wrote:
> >Robert Dawson writes:
> 
> >An important issue is that no one ran a pilot on this ballot. 
> 
> once again ... failure to do a pilot jumps up and bites one on the 
> backside
> ... a fundamental principle in research, ignored ... 
> 
> never UNderestimate the benefit one can derive from doing a trial 
> run ...
> ON THOSE WHO ULTIMATELY WILL BE the target population ... 
> 
> it would only have taken probably 10 potential voters to view and 
> have
> confusion about this ballot expressed ... 
> ==
> dennis roberts, penn state university
> educational psychology, 8148632401
> http://roberts.ed.psu.edu/users/droberts/drober~1.htm
> 
> 
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Laplace quote

[Alan McLean]

Laplace once said: 'Probability is merely common sense reduced to
numbers.'

Can anyone provide a reference for this?

My thanks,
Alan McLean


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Re: Help needed ... :-(

[David Heiser]

Based on the problems we have in ansering vague questions on edstat, I can
say that any requestor must be able to state the question, so we here (using
American English) can understand what he is saying and give a helpful
answer.

It is obvious that all of us have problems understanding the questions in
English. The complex field of statistics involves so many variations and
such a large body of knowledge, that giving a helpful answer is not easy. I
just don't reply in areas that I am weak in.

The issue is not on an individual being from Germany, or on international
relations, or on responding to people from different cultures and countries,
etc., etc. ; the issue is that the requestor should be able to state the
question so we can understand it. If he can state the question in German, do
it. Requestors post questions in Spanish, Italian, Swedish and in other
languages that I can't recognise, and get answers. Let us encourage those on
edstat from foreign countries to answer the questions in their own languages
and to use their own references. If edstat is to be truely international, we
need a lot mre questions and responses in other languages.

DAHeiser



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Re: Fwd: Butterfly ballots (fwd)

[Rich Ulrich]

On Tue, 14 Nov 2000 22:02:09 GMT, [EMAIL PROTECTED] (J. Williams)
wrote:

> In today's local paper here on the Space Coast of Florida, an
> elementary school teacher divided her 4th grade language arts class of
> varied abilities into 3 distinct groups of 11 students.  Each  group
> was asked to vote using the butterfly ballot now being questioned.
> One group was asked to vote for Gore, the second for Bush, and lastly
> for Buchanan.  Without exception all the kids marked the ballots
> correctly.  A couple of days ago, the newspaper published another
> similar study of 77 elementary school kids again with the same
> results.  Interestingly, the paper endorsed V.P. Gore and supports a

 - well, it is an unfortunately flawed  introduction to the science.
Isn't it so much nicer when examples actually  *illustrate*  the
problems that every expert will recognize? instead of failing to show
them, because of inadequacy of the experiment?  The Canadian trial was
large enough to show the point, just barely.

The first set.  There were 33 subjects, but only 11 were in the
condition ("vote for Gore") where an error is created by the layout --
from several examples, it shows  at a 5% rate, among people who (say)
may have problems with vision, etc., and are not primed for a quiz on
alertness.  5% gives about a 50-50 chance of seeing it in the test.
Oh, 5% error, that would imply that more than 10,000 Gore-votes were
omitted.  (The margin for not-having an automatic recount was about
2900.)  So maybe the rate is less than 5%.

-- 
Rich Ulrich, [EMAIL PROTECTED]
http://www.pitt.edu/~wpilib/index.html


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Re: Fwd: Butterfly ballots (fwd)

[J. Williams]

On Tue, 14 Nov 2000 22:17:31 GMT, Ronald Bloom <[EMAIL PROTECTED]>
wrote:

>J. Williams <[EMAIL PROTECTED]> wrote:
>> 
>> In today's local paper here on the Space Coast of Florida, an
>> elementary school teacher divided her 4th grade language arts class of
>> varied abilities into 3 distinct groups of 11 students.  Each  group
>> was asked to vote using the butterfly ballot now being questioned.
>> One group was asked to vote for Gore, the second for Bush, and lastly
>> for Buchanan.  Without exception all the kids marked the ballots
>> correctly.  A couple of days ago, the newspaper published another
>> similar study of 77 elementary school kids again with the same
>> results.  Interestingly, the paper endorsed V.P. Gore and supports a
>> recount.  
>> 
>
> Would the group  of kids doing a post-hoc experiment be
>biased inasmuch as the nature of the problem at hand may
>have become common-knowledge by now; even among kids; and
>so one would be forewarned of the error-mode in question,
>and be much less likely to fall into that mode of error?
>
>At any rate, what inference am I being prompted to draw here? 
>That the people who claimed to have been confused were
>either (a) ignoramuses or (b) changing their tune after
>the fact?
>
>Is there some more generous interpretation, (c), say?
>
Sure, those who complained were truly confused.  

BTW, it is my understanding  each voter is allowed 2 additional
ballots should a given voter make an error.  If voters were denied
these additional "attempts," then something is indeed very wrong.  I
am puzzled why in overwhelmingly Democratic precincts, those who
complained were denied the additional ballots.  Needless to say, it is
a troubling situation.


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Re: Fwd: Butterfly ballots (fwd)

[Ronald Bloom]

J. Williams <[EMAIL PROTECTED]> wrote:
> 
> In today's local paper here on the Space Coast of Florida, an
> elementary school teacher divided her 4th grade language arts class of
> varied abilities into 3 distinct groups of 11 students.  Each  group
> was asked to vote using the butterfly ballot now being questioned.
> One group was asked to vote for Gore, the second for Bush, and lastly
> for Buchanan.  Without exception all the kids marked the ballots
> correctly.  A couple of days ago, the newspaper published another
> similar study of 77 elementary school kids again with the same
> results.  Interestingly, the paper endorsed V.P. Gore and supports a
> recount.  
> 

 Would the group  of kids doing a post-hoc experiment be
biased inasmuch as the nature of the problem at hand may
have become common-knowledge by now; even among kids; and
so one would be forewarned of the error-mode in question,
and be much less likely to fall into that mode of error?

At any rate, what inference am I being prompted to draw here? 
That the people who claimed to have been confused were
either (a) ignoramuses or (b) changing their tune after
the fact?

Is there some more generous interpretation, (c), say?



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RE: 3 cheers for a pilot!

[dennis roberts]

At 02:18 PM 11/14/00 -0600, Simon, Steve, PhD wrote:
>Robert Dawson writes:

>An important issue is that no one ran a pilot on this ballot. 

once again ... failure to do a pilot jumps up and bites one on the backside
... a fundamental principle in research, ignored ... 

never UNderestimate the benefit one can derive from doing a trial run ...
ON THOSE WHO ULTIMATELY WILL BE the target population ... 

it would only have taken probably 10 potential voters to view and have
confusion about this ballot expressed ... 
==
dennis roberts, penn state university
educational psychology, 8148632401
http://roberts.ed.psu.edu/users/droberts/drober~1.htm


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Re: Fwd: Butterfly ballots (fwd)

[J. Williams]

In today's local paper here on the Space Coast of Florida, an
elementary school teacher divided her 4th grade language arts class of
varied abilities into 3 distinct groups of 11 students.  Each  group
was asked to vote using the butterfly ballot now being questioned.
One group was asked to vote for Gore, the second for Bush, and lastly
for Buchanan.  Without exception all the kids marked the ballots
correctly.  A couple of days ago, the newspaper published another
similar study of 77 elementary school kids again with the same
results.  Interestingly, the paper endorsed V.P. Gore and supports a
recount.  

On 14 Nov 2000 10:04:45 -0800, [EMAIL PROTECTED] (Bob Hayden)
wrote:


>- Forwarded message from by way of Tom Lane <[EMAIL PROTECTED]> -
>
>From [EMAIL PROTECTED] Tue Nov 14 10:03:28 2000
>Return-Path: <[EMAIL PROTECTED]>
>Received: from smtp.mathworks.com (turing.mathworks.com [144.212.95.101])
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>   for <[EMAIL PROTECTED]>; Tue, 14 Nov 2000 10:03:27 -0500 (EST)
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>Date: Tue, 14 Nov 2000 09:46:11 -0500
>To: [EMAIL PROTECTED]
>From: [EMAIL PROTECTED] (by way of Tom Lane <[EMAIL PROTECTED]>)
>Subject: Fwd: Butterfly ballots
>Content-Length: 10904
>
>Bob Smith, president-elect of the BCASA, forwarded this timely analysis
>that might be interesting to BCASA members.  -- Tom]
>
>
>Date: Mon, 13 Nov 2000 17:11:26 -0700
>Reply-To: Structural Equation Modeling Discussion Group <[EMAIL PROTECTED]>
>Sender: Structural Equation Modeling Discussion Group <[EMAIL PROTECTED]>
>From: rozeboom <[EMAIL PROTECTED]>
>Subject:  Butterfly ballots
>To: [EMAIL PROTECTED]
>
>   Since the voting-confusion issue has surfaced on Semnet, some of you may
>be interested in the following information, posted locally on our Univ. of
>Alberta
>psychology department's LAN, summarizing research done on this
>ballot-confusion
>issue by a staff member, Robert Sinclair, in amazingly fast response time.
>
>Bill R.
>
>
>
>
>The Butterfly Ballot Causes Confusion and Systematic Errors in Voting Behavior
>Robert C Sinclair
>University of Alberta
>Melvin M Mark
>The Pennsylvania State University
>Sean E Moore, Carrie A Lavis, Alexander S Soldat
>University of Alberta
>
>Two experiments investigated confusion and bias caused by the butterfly
>ballot format used in Palm Beach County in the 2000 US presidential
>election. In Study 1, Canadian students voted for Prime Minister of Canada
>on a single-column or butterfly ballot. They rated the butterfly ballot as
>significantly more confusing than the single-column format; however, they
>made no voting errors. Study 2 replicated the confusion effect with a
>nonstudent sample. Of greater importance, participants made errors only on
>the butterfly ballot. The butterfly ballot causes confusion and systematic
>errors in voting.
>
> The issue of systematic bias as a result of ballot format has
>become the focus of much controversy surrounding the outcome of the recent
>presidential election in the United States. Specifically, people have
>argued that the format of the ballot in Palm Beach County led to confusion
>and caused people who intended to vote for Al Gore to mistakenly cast votes
>for Pat Buchanan or punch two holes resulting in a voided ballot. We
>conducted two experimental studies to address this issue.
> On Wednesday, November 8, 2000 (the day after the presidential
>election), we had Canadian college students vote for Prime Minister of
>Canada using a single-column ballot format or a dual-column, butterfly
>format (analogous to the Palm Beach County-style ballot). We expected that
>students would rate the butterfly style as more confusing than the
>single-column format. However, it was unclear whether students, who are
>familiar with confusing optical scoring forms, would make errors on the
>ballot.
>Participants
> Participants were 324 introductory psychology students from two
>classes at University of Alberta. All were volunteers who participated in
>order to partially fulfill a course requirement.
>Procedure
> Ballot Construction. The ballots contained the names of the
>leaders of 10 Canadian political parties and space for a write in
>candidate. One ballot used a single-column format. The second was designed
>to emulate the dual-column, butterfly format used in Palm Beach County (at
>the time this study was conducted, to the investigators knowledge the
>actual ballot was not available on the web or in print media, and the
>ballot was constructed after seein

[ap-stat] RE: election proposal

[Joe Ward]

Does anyone know WHY so many states DON'T DO IT THIS WAY?
Perhaps the Political Science/History folks can comment.

-- Joe


Joe Ward.Health Careers High School
167 East Arrowhead Dr4646 Hamilton Wolfe
San Antonio, TX 78228-2402...San Antonio, TX 78229
Phone: 210-433-6575...Phone:  210-617-5400
Fax: 210-433-2828Fax: 210-617-5423
Email: [EMAIL PROTECTED]
http://www.ijoa.org/joeward/wardindex.html
***


- Original Message -
From: "Lee Creighton" <[EMAIL PROTECTED]>
To: "AP Statistics" <[EMAIL PROTECTED]>
Sent: Monday, November 13, 2000 8:11 AM
Subject: [ap-stat] RE: election proposal


> People are listening! This is exactly how Nebraska and Maine vote, as we
speak.
>
> It was decided after the disastrous 1824 election that the states would
have the power to manage how they pick electors, and *not* the federal
government.
>
> > -Original Message-
> > From: Jon Graetz [mailto:[EMAIL PROTECTED]]
> > Sent: Sunday, November 12, 2000 11:30 PM
> > To: AP Statistics
> > Subject: [ap-stat] RE: election proposal
> >
> >
> > I like it!  Now, to get anyone else to listen...
> >
> > Jon Graetz
> > The Miami Valley School
> > 5151 Denise Drive
> > Dayton, OH  45429
> > (937)434-
> > [EMAIL PROTECTED]
> > [EMAIL PROTECTED]
> >
> > -Original Message-
> > From: Reba Taylor [mailto:[EMAIL PROTECTED]]
> > Sent: Sunday, November 12, 2000 11:00 PM
> > To: AP Statistics
> > Subject: [ap-stat] election proposal
> >
> >
> > I've been toying with this idea:
> >
> > Each state has the same number of electors as their congressional
> > delegation:  e.g.  in VA, we have 11 congressional districts
> > + 2 senators =
> > 13 electors.
> >
> > Let's keep the electors, but have the ones representing the
> > congressional
> > districts vote the way their district  votes.  Then the 2
> > at-large electors
> > will vote the way the state as a whole votes.
> >
> > I think this is more equable than winner-take-all.  I also
> > think it would
> > be a more representative sample of the popular vote, but
> > still giving the
> > smaller states as much clout as the larger ones.
> >
> > Reba Taylor
> >
> >
> > *
> > *   Reba Taylor [EMAIL PROTECTED] *
> > * *
> > *   Home: School: *
> > * Blacksburg High School *
> > *   2418 Ridge Road 520 Patrick Henry Drive *
> > *   Blacksburg, VA 24060 Blacksburg, VA 24060 *
> > *   540-953-2421 540-951-5706 *
> > * *
> > *  AP Computer Science, AP Statistics, Math *
> > * *
> > *  Black holes are where God divided by zero. *
> > * *
> > * "Can't never could, till it tried!"  -- S.C. Taylor
> > *
> > * *
> > *
>
> ---
> You are currently subscribed to ap-stat as: [EMAIL PROTECTED]
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>
>



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mortality model

[Shareef Siddeek]

Dear Stat gurus,

 Can someone tell me what is the appropriate stochastic (natural)
mortality model for people. Thanks. Siddeek



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Re: NY Times on "statisticians' view" of election

[Rodney Sparapani]

I think Paul's idea of eliminating punch cards is probably a good one.  But, this is
really only a problem with large voting districts.  The error rate is about 32 out of
1000.  Usually, the error is an undervote, i.e. somebody voted, but it was not
counted.  For small districts, it would be rather easy to examine the ~4-5% of
undervote ballots.  Florida counties with punch card problems have two
characteristics that are preventing a quick resolution:  1) they are rather large and
2) they didn't examine the undervotes in the original count or the state-law mandated
re-count; it's only in the third count where they are considering them, which is what
is so disturbing.

Paul Thompson wrote:

> snip
>
> There is another message, probably more important, to obtain.  These methods for
> voting are simply prone to error.  Punching holes in cards has been abandoned in
> every segment of data acquisition save voting.  It is too easy to make several
> forms of errors.  As such, we must really ask: Is it time to eliminate punch card
> voting methods?  I believe that the answer is patently obvious.
>
> What then should they be replaced by?  The system should be cheap, flexible and
> verifiable.  I believe that the best system is optical scanner methods.  Optical
> scanners are stable.  They are fast.  They are based on real things - pieces of
> scanner paper.  The ballots can be quickly examined to see that they do not have
> double counts.

--
WWLD? (What Would Lombardi Do?)
Was "Name That Tune" Rigged?
Rodney Sparapani, Duke Clinical Research Institute
For addressing and schedule information
see http://www.duke.edu/~spara002




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Re: [ap-stat] RE: election proposal

[Ronald Bloom]

Herman Rubin <[EMAIL PROTECTED]> wrote:
> 
> In article <001801c04d82$38529f80$70690e3f@wards>,
> Joe Ward <[EMAIL PROTECTED]> wrote:
>>Does anyone know WHY so many states DON'T DO IT THIS WAY?
>>Perhaps the Political Science/History folks can comment.
> 
> The principal reason is that the two major parties want
> to keep their position AS PARTIES.  If you read the
> Constitution, there is no mention of parties, and it
> was expected that the Electors would be people of trust,
> who would use their judgment.  The near catastrophe of
> 1800 caused separate voting for President and Vice-President.
> 
> Even worse is plurality voting.  But doing something 
> about it would weaken the Demopublicans.
> 
> As it stands now, probably 2/3 of the people are not
> "represented" by someone who agrees with them.


  Agrees with them in respect to *what*?  Reasonable 
people may come to agreement along some dimensions
of discourse; and to no agreement along others.  
If there is to be something called "representative
government", then reasonable people will just have
to get accustomed to putting up, to some extent,
with politicians who do not "agree" with them on
every single, solitary laundry-list item that 
may be in contention at this or that point of
space or time.  Reasonable people tolerating
a certain amount of disagreement amongst each
other has a venerable name, it is called "Compromise".




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RE: Stats on Palm Beach votes

[Simon, Steve, PhD]

Robert Dawson writes:

>It's an interesting data set, an object lesson in design of
>questionnaires, and the whole episode has been genuinely educational. 

Amen to that. I used a web site on the ballot design: 

http://fury.com/galleries/palmbeach/index.php
 

to discuss the issue of questionnaire design in a class I taught yesterday.
An important issue is that no one ran a pilot on this ballot. So even though
the ballot may look reasonable at first glance, even to a democratic
commissioner, there were problems that manifested themselves on the election
day. How much better would it have been to get those problems out in the
open before election day. It would have only taken a few dozen people in the
pilot to identify problems with that ballot.

Also interesting are the comments on usability testing by Dan Bricklin that
someone was nice enough to post earlier:

http://www.bricklin.com/log/ballotusability.htm
  

A fascinating comment is "there is research that says shorter people don't
vote on ballot questions as frequently as taller people because the
questions are displayed way above their eye level on voting machines."

The various regression analyses suggested by Greg Adams:

http://madison.hss.cmu.edu/  

and John Marden

http://cuwu.editthispage.com/2000/11/08
  

are also wonderful teaching examples (thanks again to the folks on EDSTAT-L
who posted these sites). I never had a good way of explaining the
interpretation and use of predicted values and residuals in a regression
model until this county by county polling data set came along. I used the
Bush-Buchanan regression model in a class I taught last Friday, and I had
the group (mostly doctors) fascinated with Statistics.

Steve Simon, [EMAIL PROTECTED], Standard Disclaimer.
STATS: STeve's Attempt to Teach Statistics. http://www.cmh.edu/stats


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Re: Stats on Palm Beach votes

[Robert J. MacG. Dawson]

Eric Scharin wrote:


> 
> The discussions I've heard during the media coverage of this all have a
> disconcertingly political tinge to them.  There seems to be a lack of debate
> based on principle.  The principle I'm referring to the right of every
> eligible citizen to have their opinion heard and choice recorded.  If the
> voting system in place in Palm Beach hampered this fair process, then it
> needs to be investigated in an even-handed way, considering all of the data
> available.

Correct; however, it must be remembered that the results of this
particular election were highly unusual. In the absence of perfect
systems the correct criterion for a good imperfect system is that it
works with high probability; I do not see that the events of the last
few days constitute evidence that the existing American system doesn't
do so.

Neither candidate got a significant majority either of the US or
Florida vote; with a vote so close any election *will* be determined by
technicalities that even partisans would have said were irrelevant until
they knew whose ox was going to get, er, gored.

It's an interesting data set, an object lesson in design of
questionnaires, and the whole episode has been genuinely educational. 

(Speaking of "educational":  I certainly did not know until recently
that members of the Electoral College can and do cast maverick votes,
and that (so I have heard) state laws requiring the electoral college
members to vote the popular ticket are untested in court and possibly
unconstitutional. From this, it would seem that what we just observed
was not a presidential election, but a non-binding plebiscite. My mind
is still reeling!

(Up here, our Members of Parliament can and do "cross the floor" to a
different party occasionally, and could in principle bring down a
government by doing so; and the Governor-General can in principle invite
a person other than the leader of the largest party to form a
government, and this has happened. However, this is quite consistent, as
neither the concept of "party" nor of "Prime Minister" have much
constitutional existence. The official purpose of the election *is* to
elect a group of MP's, and that is what happens.)

Yours from the Great White North,

Robert Dawson


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Re: Palm Beach Stats

[Robert J. MacG. Dawson]

Paul Bernhardt wrote:
> 
> Reg Jordan wrote on 11/10/00 10:51 AM:
> 
> >It's interesting that no Republicans have claimed that the ballot was
> >misleading -- all the complaints seem to come from Democrats. Wouldn't the
> >"misleading, confusing" nature of the ballot apply equally across the
> >voting spectrum?
> 
> Bush was listed first on the ballot, and the hole to punch for him was
> also the first hole. So, no confusion if you wanted to vote for Bush. If
> you wanted to vote for Gore, the second name on the ballot, you had to
> punch the *third* hole on the ballot, the second hole being for Buchanan.
> Given the unexpectedly high number of votes for Buchanan in that county
> (3000 of about 400,000 votes cast) as in the next largest Buchanan county
> (Pinnelas (Tampa-Clearwater area), Buchanan got 1000 of the 400,000 votes
> cast). You have to argue that Palm Beach county has more conservatives
> than Pinnelas. If that's the case you would expect Bush to have done
> better in Palm Beach than Pinnelas. But, the oposite is the case. Palm
> Beach went decisively for Gore, while Pinnelas was very close to evenly
> split, with Gore leading only slightly.


Except that, curiously, the Bush-Gore split does *not* seem to be a
very good predictor of Buchanan vote. Plotting the log-transformed
proportion of Buchanan votes against the proportion of Bush votes:



 -4.0+ *
 - *
logPBpro - **
 - *
 -P *  **
 -5.0+   ** *  *   *  *  *
 -   ** * 2**
 - 2  * *  * **  *   *
 -   *  *   * * *  *
 -   *   *  *2 * *** *
 -6.0+*  2   *  ***
 -**   *
 -*   **   *
 -  *  *   * *
 -
 -7.0+ *
 -
  

--+-+-+-+-+-+Bushpro 
 0.320 0.400 0.480 0.560 0.640 0.720

The regression equation is
logPBpro = - 6.80 + 2.25 Bushpro

PredictorCoef   StDev  TP
Constant  -6.8005  0.4440 -15.310.000
Bushpro2.2484  0.7821   2.880.005

S = 0.5867  R-Sq = 11.3% R-Sq(adj) = 9.9%

There's an effect, but it's very much weaker than the relationship
between county size and Buchanan votes. Voting for Buchanan is
apparently a rural thing, not a classic left-right thing. 

-Robert Dawson


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Re: manual recount - of punched ballots

[Robert J. MacG. Dawson]

Since the technical term "chad" for the piece of card removed by a punch
has been publicised recently, I thought I'd pass on the etymological
note from the Hacker's Dictionary (E.S. Raymond, 1994, or consult 
(among other sites) http://info.astrian.net/jargon/ :)

chad /chad/ n. 1. [common] The perforated edge strips on printer
paper, after they have been separated from the printed portion. Also
called
selvage, perf, and ripoff. 2. obs. The confetti-like paper bits punched
out of cards or paper tape; this has also been called `chaff', `computer
confetti', and
`keypunch droppings'. It's reported that this was very old Army slang,
and it may now be mainstream; it has been reported seen (1993) in
directions for a
card-based voting machine in California. 

Historical note: One correspondent believes `chad' (sense 2) derives
from the Chadless keypunch (named for its inventor), which cut little
u-shaped tabs in
the card to make a hole when the tab folded back, rather than punching
out a circle/rectangle; it was clear that if the Chadless keypunch
didn't make them,
then the stuff that other keypunches made had to be `chad'. There is a
legend that the word was originally acronymic, standing for "Card Hole
Aggregate
Debris", but this has all the earmarks of a backronym. 

-Robert Dawson


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Fwd: Butterfly ballots (fwd)

[Bob Hayden]

- Forwarded message from by way of Tom Lane <[EMAIL PROTECTED]> -

>From [EMAIL PROTECTED] Tue Nov 14 10:03:28 2000
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Subject: Fwd: Butterfly ballots
Content-Length: 10904

Bob Smith, president-elect of the BCASA, forwarded this timely analysis
that might be interesting to BCASA members.  -- Tom]


Date: Mon, 13 Nov 2000 17:11:26 -0700
Reply-To: Structural Equation Modeling Discussion Group <[EMAIL PROTECTED]>
Sender: Structural Equation Modeling Discussion Group <[EMAIL PROTECTED]>
From: rozeboom <[EMAIL PROTECTED]>
Subject:  Butterfly ballots
To: [EMAIL PROTECTED]

   Since the voting-confusion issue has surfaced on Semnet, some of you may
be interested in the following information, posted locally on our Univ. of
Alberta
psychology department's LAN, summarizing research done on this
ballot-confusion
issue by a staff member, Robert Sinclair, in amazingly fast response time.

Bill R.




The Butterfly Ballot Causes Confusion and Systematic Errors in Voting Behavior
Robert C Sinclair
University of Alberta
Melvin M Mark
The Pennsylvania State University
Sean E Moore, Carrie A Lavis, Alexander S Soldat
University of Alberta

Two experiments investigated confusion and bias caused by the butterfly
ballot format used in Palm Beach County in the 2000 US presidential
election. In Study 1, Canadian students voted for Prime Minister of Canada
on a single-column or butterfly ballot. They rated the butterfly ballot as
significantly more confusing than the single-column format; however, they
made no voting errors. Study 2 replicated the confusion effect with a
nonstudent sample. Of greater importance, participants made errors only on
the butterfly ballot. The butterfly ballot causes confusion and systematic
errors in voting.

 The issue of systematic bias as a result of ballot format has
become the focus of much controversy surrounding the outcome of the recent
presidential election in the United States. Specifically, people have
argued that the format of the ballot in Palm Beach County led to confusion
and caused people who intended to vote for Al Gore to mistakenly cast votes
for Pat Buchanan or punch two holes resulting in a voided ballot. We
conducted two experimental studies to address this issue.
 On Wednesday, November 8, 2000 (the day after the presidential
election), we had Canadian college students vote for Prime Minister of
Canada using a single-column ballot format or a dual-column, butterfly
format (analogous to the Palm Beach County-style ballot). We expected that
students would rate the butterfly style as more confusing than the
single-column format. However, it was unclear whether students, who are
familiar with confusing optical scoring forms, would make errors on the
ballot.
Participants
 Participants were 324 introductory psychology students from two
classes at University of Alberta. All were volunteers who participated in
order to partially fulfill a course requirement.
Procedure
 Ballot Construction. The ballots contained the names of the
leaders of 10 Canadian political parties and space for a write in
candidate. One ballot used a single-column format. The second was designed
to emulate the dual-column, butterfly format used in Palm Beach County (at
the time this study was conducted, to the investigators knowledge the
actual ballot was not available on the web or in print media, and the
ballot was constructed after seeing it displayed for a brief period on
CNN). The butterfly ballot was designed so that the leaders of the 2
predominant parties appeared in the first and second positions in the first
column. Specifically, Stockwell Day, leader of the Canadian Alliance Party,
was in the first position on the ballot, corresponding to George Bush on
the Palm Beach County ballot, and Jean Chretien, leader of the Liberal
Party of Canada, was in the second position, corresponding to Al Gore. The
leader of a third party, expected to receive few votes, was the first name
to appear in the second column. Specifically, Joe Clark, leader of the
Progressive Conservative Party of Canada, was in the position on the ballot
corresponding to Pat Buchanan on the Palm Beach County ballot. The
r

help: weighted robust regression

[Patrick Agin]

Hi,

Does someone know how to include weights in the S-Plus rdl1.s algorithm
(the robust regression algorithm developed by Hubert & Rousseeuw)? Of
course, the algorithm already include a weighting scheme (based on
distances of x points w.r.t. a robust center of an ellipsoid) but I
want, before entering the procedure, to put more weights on some
x-points and less on some others. Does it make sense? If so, how can we
do that?

I considered using the lmRobMM function (the algorithm developped by
Yohai et al, also available in S-Plus) because it includes a "weights"
argument but my problem includes regressors that are continuous and
others that are binary and I don't know if the algorithm can handle such
categorical variables. Even if it's the case, the default number of
random subsamples drawn (and needed by the algorithm) is 4.6*2^ncol(x);
I have 10 continuous variables + 1 categorical with 20 levels (which
recoded gives 20 dummy vars), so the total is 30. Of course, I could
change this default number and set a more "reasonable" one but the
choice would be inevitably so small with regard to the default that I
seriously doubt about the validity of the result anyway.

Can someone help?

The exact references for the above cited papers are:

   * Robust regression with both continuous and binary regressors, Mia
 Hubert and Peter J. Rousseeuw.
 http://win-www.uia.ac.be/u/statis/publicat/#j1990
   * Yohai, V., Stahel, W. A., and Zamar, R. H. (1991). A procedure for
 robust estimation and inference in linear regression, in Stahel, W.
 A. and Weisberg, S. W., Eds.,  Directions in robust statistics and
 diagnostics, Part II.  Springer-Verlag.

Patrick




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Re: manual recount - of punched ballots

[Bert Bishop]

Thom Baguley wrote:

> I fail to see how the punch card improves on this (IMO it is worse
> because you simply can not fold it - or it won't go through the machine).
>
> Thom

The punch card is put into a folder concealing the punches.  Folder and card
are deposited into the ballot box.





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Re: manual recount - of punched ballots

[Thom Baguley]

Ron Hardin wrote:

> Rich Ulrich wrote:
> > With 10,000 no-punches where only half that many no-votes should be
> > expected (in Palm Beach County), they re-counted a 1% sample and came
> > up with 47 additional votes -- about half of the 100 or so that were
> > possible, and consistent with the number of no-votes that typically
> > are seen.  There was no report of how many no-punches had existed.
> > Gore gained, as he was expected to, because Gore carried the county by
> > almost 2-to-1.
>
> Say punched cards have a 5% reject rate, a figure I've heard several
> times, then a manual count without bias always raises the totals
> in proportion to the existing votes.  Thus as you say, a Democratic
> county manually counted picks up net Democratic votes.
>
> Would you say that therefore a Republican county with the reversed
> numbers ought to be manually counted as well, if a Democratic one

I'm not a US citizen, and not privy to your arcane electoral practices, but
as I understand it, the counting procedures vary from county to county and
state to state. All counties which use the punch hole system ought to be
recounted manually as the level of error (5%) is very high and non-random
(because not all counties used it).

AFAIK this is unheard of in General Election in Western Europe - even in
federal countries like Germany the same design of ballots and counting
procedures are used in diferent states.

>
> is?  Otherwise it would seem a net Democratic gain is guaranteed.
> The county that hand counts wins an even election.
>
> The benefit of the machine counts is the avoidance of bias.  The
> sign of the difference at the end of it all is an excellent estimate,
> not biased, though the totals are biased low by machine counting.

That's simply false.

Bias in a statistical sense can be introduced to a procedure by machines or
voting systems. (Bias in this sense carries no necessary implication of
human intent to cause said bias). As we are in a statistical newsgroup I'm
assuming the statistical sense was intended by most posters. Bias can be
introduced quite easily e.g. if the machines that produce errors are no
distributed across counties in a way that balances out errors between
candidates. It can also be introduced if human factors (e.g., say age) are
more likely to produce an error with that machine type AND those human
factors (e.g., age) are correlated with voter intention. You can come up
with other examples quite easily.

> A hand count improves the totals but ruins the differences.  But what
> you want is the differences, ie the winner, not the totals.

Possibly. But how can you calculate the correct differences without
calculating the true totals in each county?

You might want to read up on the ecological fallacy and Simpson's paradox.
Because the individual counties are not homogeneous and because error is
not distributed in a balanced way (or even randomly) there is no way to
calculate the true difference without getting the best possible counts in
each county.

>
> I have heard that punch cards are favored because they retain
> vote privacy, and they consider the 5% drop rate acceptable.

In the UK (apart from the recent elections for London Mayor - which weren't
punch card ballots) we use hand counts and get error rates far, far lower
than this (usually far less than 0.5%). Voter privacy is maintained by
voting behind a curtain and folding the ballot paper in half before putting
it in the ballot box. The paper has a ballot number which can be matched to
counterfoils with the electoral number, but only by use of a High Court
order. I fail to see how the punch card improves on this (IMO it is worse
because you simply can not fold it - or it won't go through the machine).

Thom






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Re: Help needed ... :-(

[Dennis]

> ---
> What you need is a good class in written English
> DAH
>

Yes, you are right. But I still haven't found one yet. Private Language
Schools are too expensive here.




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