The Clock Auction Steptype is including four types of auctions in itself. The basic idea for all of the auctions is a timer counting down for multiple intervals. When the timer gets to zero, the displayed price is either ascending or descending, depending on the auction type. At any point of the auction, the participants are able to bid at the current price on the clock.
Within the Auction Options tab of the Steptype all the necessary parameters for the auction can be configured.
At first the Auction Direction is specified. The Auction Direction is dependent on the Auction Type as well. The combination of these two parameters defines the four auction types that were mentioned earlier and all of the four configurations will be explained hereafter.
An English Auction as a Forward Auction is an auction, where the price is ascending with each interval. Whenever a participant is bidding for the current price on the clock, the participant leaves the auction. In this auction, the participant represents a buyer who decides to bid the maximum price he is willing to pay. Therefore, the last remaining participant in the auction does not need to bid and wins the auction with the current price on the clock. He gets transferred to the next step automatically.
In an English Auction as a Reverse Auction the participants represent sellers instead. For that reason the price is decreasing with each interval and the maximum price the buyers were willing to pay turn into a minimum price the sellers are willing to pay. Other than that the functionality of the auction type is equal to a Forward Auction which is described above.
In contrast a Dutch Auction as a Forward Auction adjusts the price in a direction that favors the participants. The role of the participant is the same as for the Forward Auction in an English Auction, so the participants are buyers. What changes is the functionality of the bidding. The first participant to bid wins the auction at the current price on the clock and all the other participants get transferred to the next step.
The Dutch Auction as a Reverse Auction has the same functionalities as the Forward Auction described above. The only difference is the change of the role of the participants as sellers again and an ascending price as a result.
The Grouping of the experiment participants can be decided between Group Everyone, Group by Grouping or Group by Variable (PSL). Group Everyone results in all participants in the experiment bidding in the same auction. All of them will see the same current price and the timer will be the same as well. There will be one winner only. Group by Grouping on the other hand is dependent on how many groups are participating in the experiment. Each group will have a separate auction. The last option Group by Variable (PSL) is the most flexible. Before the Clock Auction Steptype, a Grouping Variable (Name / PSL) needs to be specified for every participant. The context of the variable has to be PSL, which is further specified in the variable context documentation. The name of the specified variable has to be entered here in the Auction Options.
Within the screen of the participants during the experiment it is possible to Display number of participants. The displayed number represents the number of participants, which are participating in the auction at the current moment. The number gets updated in real-time. Next to this number in the top right corner of the screen, the timer is shown, when the Display Interval Timer checkbox is selected. The Time Interval (in seconds) defines, how long one interval takes.
The Display Interval Circle is displaying a circle around the current price on the clock, when the checkbox is selected. This circle displays the time per interval, therefore the time to draw a full circle is based on the Time Interval (in seconds) parameter. A full circle represents one full intervall, an empty circle shows that a new interval is beginning. The Circle Radius (in px) as well as the Line Width (in px) is configurable within the Auction Layout Tab.
A Monetary Interval is the change to the current price on the clock at the end of each time interval. The price will be decreased or increased based on the Auction Direction and the Auction Type, as described earlier. The Amount of Intervals describe the amount of increases or decreases of the price until the auction ends. The initial starting price for the auction is defined by the Opening Bid.
Due to delay based on slow connections, it is possible to define a Bid Time Tolerance (in ms). Whenever the submitted bid and the current price on the clock differ, the system compares the timestamp of the submitted bid with the timestamp on the server and is taking the bid time tolerance into account. If the bid was within the range of the bid time tolerance, the bid will be accepted.
Another delay based issue that might occur is solved by the Delay Before Start (in ms). Because of slow connections the loading time for the auction step might take longer for different participants. For that reason the delay before start can be defined. Participants arriving early on the page will already see the auction and the auction is beginning, after the first participant arrived plus the defined milliseconds of delay.
A Bid Taker can be specified as well. This participant will not participate in the auction actively. He does have all the necessary information during the time of the auction and can decide on the winner after the auction finished. The Bid Taker option currently only works for the Group by Grouping setup and will be extended in the future.