Jared - Ø In shopping cart and checkout systems, things are rarely as easy as they seem. You could substitute many things for 'shopping cart and checkout' but it's our job as designers to make this 'magic' happen with minimum inconvenience to users. Naturally, it's a trade off, but my feeling is that it just doesn't help very much to ask for the credit card type. It's virtually impossible to get a valid credit card number from a missed digit and you already have name, expiry date CCV, address and DNA sample to fall back on. (I was kidding about the DNA sample, but the guy who invented DNA fingerprinting apparently foresees a world where we would just spit into something to make a payment - it sounds unhygienic to me! See the current issue of New Scientist.) Regards,
William From: Jared Spool [mailto:[email protected]] Sent: 29 September 2009 2:18 PM To: William Hudson Cc: Amy Jones; [email protected] Subject: Re: [IxDA Discuss] Is there a good reason to require people to idtheir credit card? On Sep 29, 2009, at 4:56 AM, William Hudson wrote: There are many sources for credit card prefixes (as well as check digit algorithms) for validating credit cards. For example, http://en.wikipedia.org/wiki/Bank_card_number Part of the problem, as pointed out by the chart, is different cards have different number lengths. They range from 13 digits to 16 digits. For example, someone who accidentally leaves the first digit off of their mastercard or visa could look like a valid amex card. Again, it depends when you're doing your authorization check. If you're processing immediately during the users' session, you don't need to ask for the card type because an entry error will be caught (assuming you've got a decent merchant processor). However, lots of purchase systems do a deferred authorization check, to allow the seller to have a look at the transaction before its put through the system (often for additional fraud protection or inventory clearance). In this instance, it's better to ask for the card type to give you a piece of redundant information for the validity check. In shopping cart and checkout systems, things are rarely as easy as they seem. Jared Jared M. Spool User Interface Engineering 510 Turnpike St., Suite 102, North Andover, MA 01845 e: [email protected] p: +1 978 327 5561 http://uie.com Blog: http://uie.com/brainsparks Twitter: @jmspool ________________________________________________________________ Welcome to the Interaction Design Association (IxDA)! To post to this list ....... [email protected] Unsubscribe ................ http://www.ixda.org/unsubscribe List Guidelines ............ http://www.ixda.org/guidelines List Help .................. http://www.ixda.org/help
