Autor:
PeterL
Titel: Re: Ständig überboten trotz höherem Höchstgebot
Verfasst am: 02.06.2013 - 19:35 (GMT 1)
EBay's bidding algorithm has 4 rules:
1 The highest bid wins.
2 The earlier of two equal bids wins.
3 Each bid must be greater than the previous bid by a minimum interval, which depends on the previous bid amount. This interval is set by EBay, and increases with the bidding level.
4 Each human-entered bid is a bid MAXIMUM. The EBay autobidding system enters autobids following the previous rules, so that the final price is the lowest price that satisfies the rules.
EBay's automatic bidding system enters bids up to a bidder's maximum, so you don't have to watch the bidding. If the current bid by 'B' is 12, but no one else has bid, the price could be at 2. When you ('A') bid 20, EBay enters autobids for both bidders up to their maximums:
A-3
B-4
A-5
B-6
A-7
B-8
A-9
B-10
A-11
B-12
A-13
until someone enters a bid>13.
The way we humans understand things, the rules should apply in the order above, because the rules are transitive; that is the end result depends on the order the rules are applied. Complex systems and computer algorithms sometimes produce unexpected results. Computers have no common sense. If EBay's bidding algorithm applies rule 3 before rules 1 & 2, by using its autobidding algorithm, you would get unexpected and undesirable results.
E.g.:
Rule 1:
A bids 21,
B bids 20
Regardless of when the bids are entered, A should always win. (Rule precedence= 1,2,3,4)
The final price could be less than 20: if the bid interval is 2, and A's last autobid was 18.01, B cannot bid less than 20.01, but that's over B's limit, so no bid is made, and A wins for 18.01, which is less than B's maximum bid.
(Result- unexpected, but not undesirable, since A would have won based on maximum bids, and A actually got a better price than they might have.)
It is conceivable that the situation above could allow B to win. (Rule precedence= 4,3,1,2) If B's last autobid is 19.01, A cannot bid less than 21.01, but that's over A's limit, so no bid is made, and B wins for 19.01, which is less than A's maximum bid.
(Result- unexpected and not as intended, since we expect Rule 1 to prevail.) I believe, but I'm not sure, that EBay's algorithm avoids this.
If two bids are equal, EBay accepts the earlier bid:
A bids 20 on Jan 1 1900,
B bids 20 on Jan 5 1900.
Auction ends Jan 5 1900.
A should always win.
However, depending how smart the autobidding algorithm is, it is conceivable that the situation above could arise, (Rule precedence= 4,3,1,2) so that B's last bid is 18.01, and A cannot bid, so B would win for 18.01.
(Result- unexpected and not as intended, since we expect Rule 2 to prevail.) I believe, but I'm not sure, that EBay's algorithm avoids this.
Murphy's Law always applies. Complex systems and computer algorithms can produce unexpected results. Computers have no common sense.
I hope this helps.
