Data exploration
Do Auction Winners Overbid?
A historical distribution of final-marked, highest-observed bid steps relative to other positive steps in the same auction trace.
Abstract
This study examines whether the final marked step in a historical property auction trace was unusually large relative to that trace’s earlier positive steps. It follows the original analysis flow, but uses a stricter eligibility rule and publishes only reviewed aggregates.
Of 524 eligible traces, 61 (11.6%) had a final marked step above 2× the mean of their other positive steps. This is a descriptive pattern, not an estimate of overpayment or the smallest step that could have succeeded.
1. Dataset Overview
The reviewed snapshot begins with 892 historical auction groups recorded from 16 January 2019 to 19 October 2019. Each successive check narrows that set before any final-step ratio is calculated.
- Auction groups
- 892
- One final marker
- 888
- Positive final step
- 631
- Strictly eligible
- 524
Figure 1
Eligibility flow
- 892 Auction groups
- 888 Exactly one final marker
- 631 Positive marked step
- 531 Other positive steps available
- 524 Also highest and latest observed
2. Methodology
2.1 Definition of a large final step
A trace is included only when it has exactly one source-marked final row, that row has a positive step, and at least one other positive step is available for comparison. The marked row must also be both the highest and latest observed row in the trace.
Large final step = final-marked positive step > 2× the mean of the trace’s other positive steps
The 2× boundary is an analyst-defined descriptive rule. It is not an economic, legal, or causal definition.
2.2 Final-step ratio
For every eligible trace, the final marked step is compared with the mean size of its other positive steps.
- 01 Group the historical observations by auction trace and identify traces with exactly one source-marked final row.
- 02 Apply the positive-step, comparison-step, highest-observed, and latest-observed eligibility checks.
- 03 Calculate one ratio per eligible trace and summarize those ratios into fixed aggregate bands.
Why the public method is stricter
The source’s final marker is retained, then checked against ordering and observed height. This avoids treating a marked row as final when the trace itself does not support that interpretation.
3. Findings: General Bidding Patterns
The source paper also explores starting-to-final price changes and bidder participation. Those outputs are not part of the reviewed public aggregate snapshot, so this static port does not reproduce them or carry over their broader behavioral claims.
Static scope retained for review
The public evidence begins with the eligibility flow in Figure 1 and then narrows to the final-step ratio distribution in Figure 2. This preserves the paper’s analytical sequence without publishing prices, bidder counts, auction records, or unreviewed source aggregates.
4. Findings: Bid Jump Analysis
The distribution describes how the final marked step compared with the trace’s other positive steps across the 524 eligible traces.
- Eligible traces
- 524
- Above 2×
- 11.6%
- Traces above 2×
- 61
- Median ratio
- 0.7692×
Figure 2
Final marked step relative to other positive steps
Finding 4.1: Large final steps were a minority pattern
11.6% of eligible traces crossed 2×, while the median ratio remained below 1×. The evidence supports a frequency statement about this snapshot; it does not identify why any individual step was large.
5. Data Explorer
The interactive page exposed filters and expandable auction histories. This public version replaces that raw explorer with the complete reviewed aggregate distribution used in Figure 2.
| Ratio band | Traces | Share |
|---|---|---|
| At most 1× | 360 | 68.7% |
| Above 1× to 2× | 103 | 19.7% |
| Above 2× to 3× | 26 | 5.0% |
| Above 3× to 5× | 21 | 4.0% |
| Above 5× | 14 | 2.7% |
What this snapshot can be used for
It allows the historical ratio distribution and the 2× threshold result to be inspected without publishing auction identifiers, prices, individual bid histories, or record-level dates.
6. Conclusions
Most final steps did not exceed the comparison mean
68.7% of eligible traces had a final-step ratio at or below 1×.
The 2× pattern was measurable but uncommon
61 of 524 eligible traces crossed the analyst-defined threshold.
The ratio cannot explain bidder behavior
The snapshot describes observed step sizes only. It does not establish intent, necessity, avoidable cost, or a counterfactual closing price.
Limits
What the recorded traces cannot establish.
- The source marker is treated as “final,” but the ingestion contract does not prove a legally settled sale or identify a verified winner.
- The comparison mean contains observed positive steps; it does not model another participant’s willingness, timing, or counterfactual response.
- A step above 2× does not establish overpayment, buyer intent, avoidable cost, or the price at which the sale could have closed.
- The snapshot covers one historical source and period. Geography, collection completeness, and current representativeness are not established.
- No prices, monetary amounts, bidder markers, auction identifiers, record-level dates, or bid histories are published.
This is a static descriptive note based on a reviewed historical aggregate snapshot. It is not a valuation, prediction, recommendation, or assessment of any individual transaction.