Motivation
The philosophy behind jAuctions is to provide a suite of auction programs that can be used for a wide variety of auction experiments. While it would be unrealistic to try to build from scratch a general-purpose auction program that fits all and everyone's needs, jAuctions attempts to provide a framework general and flexible enough to be able to incorporate additional features that may be requested in the future.

Specifics
jAuctions is Java-based and can be accessed though the web, thereby allowing for flexible use by experimenters and participation by subjects. In addition, jAuctions provides flexibility along the following dimensions:

• Auction Formats: ascending (English), descending (Dutch), sealed bid (k-th price), allpay, etc., and combinations of these.
• Valuation Structures: general distributions for both private and/or common values.
• Multiple Units and Package Bidding: the focus is on multi-unit auctions (although standard single-unit auctions are included). Of special interest is the case where there are synergies between the items sold so that the possibility of combinatorial or package bidding becomes relevant. Several formats with and without package bidding will be included.
• Single and Double-Sided Auctions: the option of sellers submitting asks will be included, resulting in two-sided (combinatorial) auctions with a discrete round structure.
• Win, Budget, and Activity Constraints: allowing the experimenter to determine the pace of the auction and to impose caps on bids and number of items that can be won.
• Other Features: alternative matching protocols, group size, bidder-specific reserve prices, etc.

Release
jAuctions will be made available for researchers interested in auction experiments. Once the code is stable enough and sufficiently tested, researchers can request a copy of the code as long as they make additions and improvements available to other users. The current estimate for the first release is fall 2006.

People
jAuctions is being developed by Charlie Hornberger and Walter Yuan at Caltech. Jacob Goeree is the initiator and scientific advisor for the project.

Acknowledgements
The development of jAuctions is being made possible by the generous support of the Dutch National Science Foundation NWO for my VICI project "License Auctions: Theory, Policy, and Experiments." NWO allows me to pursue my VICI project at Caltech, which is being administered by the Department of Economics at the University of Amsterdam.