How Do I Use the "Bidding History vs. Time" Chart?

This tool is most most helpful to analyze auction(s) that have a of bidding activity. Naturally, the more bids, the more helpful the chart. This tool originated from a discussion we had about how, for each auction, the bidding table shows the personality and behavior of each competing bidder. That led to the idea of trying to show it using a graph.

Time Always Goes Left-to-Right

Going left-to-right (the X-axis) is time. The vertical axis is price. The far left is the auction start time. The far left is the auction ending time. The bids are shown on the chart according to the time they were placed. As you will notice over time using, it, every auction has a unique "personality" that is reflected in the bid history.

Lines Going Backward Denote Proxy Bids

The first thing you will notice is that sometimes, the line goes back in time, as per the example shown below. This is due to how eBay's proxy bidding system works, and really helps newcomer. Each time eBay receives a bid, it must "pass through" all of the other previous bid values to determine the true price. The price is the highest bid plus the minimum bid increment. That's why the chart seems to go back in time --- it does. The chart shows which bid is used to determine the next-latest bid.

When a bid is placed manually, but the previous bidder remains the high bidder, this is represented on the chart as going back in time to account for the highest bid, which occurred in the past and is still the dominant bid. This is the method used to raise the price by only the minimum that is required. When a new bid is placed, eBay evaluates the current price for the latest bid by "going back in time" to review the next-highest bid. For more information on this subject, see the help page for proxy bidding.

Example Showing a Sniper Winning

The following chart shows a sniper using won an auction by hiding their interest and bidding at the last second. The X axis is time, going from left to right. The Y axis shows the value of each bid. Notice that, right at the end of the auction, several bidders manually "climbed the ladder," that is, they kept increasing their bid until they were the high bidder. Then, right at the last second, won the auction by placing the bid in the last few seconds.

Example of Reaching Market Value Quickly

In the next example, many bidders competed within a few hours of the auction starting. The item reached market value very quickly:

Some Other Things to Notice

Some other things ton otice in the above examples:

• Each dot on the chart represents a bid.
• Only the high bid for each bidder is shown. (To show every bid involved in the calculation made the chart too difficult to read.)
• The chart will show up to 5 items at a time. If you don't see the item(s) of interest, use the filters.
• Reading from left to right, the auction begins at the starting price, near zero. The horizontal dotted line that runs across the top of the chart is the Bid Line. This line represents the amount of your snipe bid (if one exists).
  1. At point 1, Bidder #1 places a bid. She is happy because she is the first bidder, and is therefore the high bidder.
  2. A short while later, at point 2, Bidder #2 bids. His face is sad because he was outbid by a proxy bid. The cost of the auction was raised to Bidder #1's bid, plus the bid increment. He decides not to continue bidding.
  3. At point 3, Bidder #3's bid is higher than the highest bid plus the increment. Her bid reveals Bidder #1's bid value, so all of the information about Bidders #1 and #2 are now known. The graph shows how the current price calculation must first "pass through" Bidder #1.
  4. The resulting price is Bidder #1's bid plus one bid increment.

How to Fine-Tune the Chart

• Toggle groups of items on or off by clicking on them in the legend on the right.
• Hover over a datapoint for the details for that auction.
• Enter text into the search filter to limit the items on the chart to only items that contain your text string in the item title.
• Change the price range of auctions shown.

See Also

• Win Rate Table
• Snipe Bid vs. Cost Chart
• "Perfect Pennny" Chart
• Bid Spending Chart