I have worked with many museums and most cannot afford the barcode/scanning technology. Double counting cannot be avoided unless you get the name of each visitor. Therefore a walk-up customer who chooses to come again next week is counted twice. Same day sales should be fine given you reference the same sale record in your admission system. If you are not using an admission system double counting may occur. If you consider the barcode route you want to use a computerized ticketing system with access control. You then can scan tickets whenever and wherever you want. You can then do in depth tracking and visitation analysis. This is rare to nonexistent in museums. The concept of tracking a customer by constantly asking for a ticket can be seen as intrusive. Some museums have considered RFID. The problem is you need an active RFID tag and these cost around $10 a tag. Not a disposable technology and it's akin to placing dog collar on visitors. I would say most museums are not about creating this kind of environment. A passive RFID would require you to issue wristband which may work. However, must cultural visitors may view the wristband as something you get at a theme park not a museum. ========================================================= Important Subscriber Information: The Museum-L FAQ file is located at http://www.finalchapter.com/museum-l-faq/ . You may obtain detailed information about the listserv commands by sending a one line e-mail message to [log in to unmask] . The body of the message should read "help" (without the quotes). If you decide to leave Museum-L, please send a one line e-mail message to [log in to unmask] . The body of the message should read "Signoff Museum-L" (without the quotes).