Word of the Day: Tech Definitions from WhatIs.com

Nov 3 2008   3:46PM GMT

Overheard: Touch screens, vote flipping and fear of touch screen parallax

Margaret Rouse Margaret Rouse Profile: Margaret Rouse

vote-button.jpg Even though new standards were developed in 2005 and 2007, all voting machines in use today are only certified to the 2002 standards.

Declan McCullagh, E-voting worries linger as Election Day nears

There’s lots of buzz about “vote flipping” on touch screen voting machines. It’s like we’re all acting as if touch screen voting uses some new technology that’s prone to errors. Like the touch screen of a voting machine is magic or evil — or Republican.

Duh. It’s the same technology we use whenever we take money out of an ATM machine. I think it makes more sense to be nervous about the fact that our voting technology is only up to 2002 standardsAlex Howard gives you the scoop on who’s using what.  Or click on this interactive map from ComputerWorld that tells you what voting technology is being used in each state.

But back to vote flipping. The tech “bug” behind vote flipping has a real name. It’s called “touch screen parallax.”  Parallax simply means “The difference in appearance or position of an object when viewed from two different locations.”

Kids like to play with the concept. Remember when you were a kid and would pick a focal point and close your right eye — and then you’d quickly switch eyes and the object would seem to magically move? (You knew the object didn’t really move; you were just looking at it from a different position on your face but it did seem rather mysterious.)

Well years ago, if you went to a bank’s drive-through and used the ATM machine,  the touch screen could be a little “off” depending on the light source, time of day — or whether you were sitting high up in a truck or close to the ground in a little Mini-Cooper.

Banks have done a good job overcoming the parallax problem. Their solution? Calibrate the machines often and make sure the image maps are large enough to accommodate parallax errors. Plain English? The ATM machine runs a little program periodically on the back-end that maps a series of cross-hairs to the button images.  And the programmers made the button images BIGGER so there’s less chance the user accidentally touches the wrong part of the screen.

So what should you do if you intend to vote for McCain on a touch screen voting machine and Obama is the name that lights up?

The parallax isn’t going to change while you’re in the booth. You can move and angle your field of vision differently, use a different finger (no comments, please)  and see if that works — or you can ask a polling representative for assistance.

If the poll worker determines that the voting machine is calibrated incorrectly, they can cancel the ballot and put the machine in administrative mode. This will let them re-calibrate the screen and then you can vote.


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