Originally Posted by gamecat

Let me put it this way: fuzzy logic is desirable in autonomous systems for a reason. Since sniping programs don't offer that kind of intelligence, I find it necessary to supplement them with my own.

Sweet Lou, I don't think I said anything that is very difficult to understand. I don't generally aim to buy bikes for what I think their highest possible market value is, I want to buy them under value or at least at the low end of that range. Given the structure of ebay auctions and the use of sniping, it's impossible to gauge the true interest of other buyers until the last few moments. I don't think your dismissal of the influence of other buyers is wise, and I invite you to reread what I wrote. If you're buying a bike to flip it, and you're expecting to sell it for $400 in your local market and have decided it's "worth" $220 to you then we can say you expect to make a profit of $180. Now, if somone comes along and snipes your snipe @ $225 you may be able to hit back manually at $230. If you win, then you have defeated another automated snipe and you get to make $170 vs. the expected $180 rather than being left with $0. On the other hand, if the other bidder manages to respond, then you know there's another human out there and you can back off to avoid a bidding war. Your estimation of it's worth may still be $220, but by having the flexibility to compromise on that valuation at the last minute you retain almost all of the expected profit. Now perhaps you would suggest that I should be willing to bid up to $390 in this circumstance, or should pick some arbitrary price in between--and I would respond that given the structure of an eBay auction vs. a live auction it is not structurally advantageous to do so. You end up paying more, as the price is bid up before others are dissuaded, or as snipes come in.

That said, I'd prefer to let this go. I don't want to get into a religious war between classical and behavioral economic models.