H199: favourite at a big price in a big handicap

Mechanism and rationale

The favourite at 5/1 or bigger in a handicap of 14+ runners. Prices are compared with same-priced horses, most of which are fourth or fifth choice in smaller races; being the one the whole market settled on should be worth more than the price says.

The rule

is_handicap = 1 AND is_favourite = 1 AND sp_decimal >= 6 AND field_size >= 14

Reads: is_handicap, is_favourite, sp_decimal, field_size

Pre-registration

Spec hash (sha256 of the canonical pre-spec)

not designed yet

Frozen

not frozen

The definition can still change.

Broad

is_handicap = 1 AND is_favourite = 1 AND sp_decimal >= 6 AND field_size >= 14

Kind

all

Origin

research/experiments/overnight/results_v2.jsonl

Refinements

[
  {
    "name": "Flat",
    "rule": "(is_handicap = 1 AND is_favourite = 1 AND sp_decimal >= 6 AND field_size >= 14) AND (race_type = 'Flat')"
  },
  {
    "name": "jumps",
    "rule": "(is_handicap = 1 AND is_favourite = 1 AND sp_decimal >= 6 AND field_size >= 14) AND (race_type IN ('Hurdle', 'Chase'))"
  },
  {
    "name": "sole favourite",
    "rule": "(is_handicap = 1 AND is_favourite = 1 AND sp_decimal >= 6 AND field_size >= 14) AND (favourites = 1)"
  }
]

Tier

B

Result (from the archive)

info sole favourite · 15 Oct, 23:10

Bets

556

A/E

1.11

winners vs the prices

SP return

-11.3%

level stakes

Betfair SP return

+27.2%

49 bets with a BSP

Strike rate 13.8%.

Falsification

No attacks yet. Only promising ideas are attacked.

Sealed holdout (vault)

Not queried. Only a frozen idea can spend its one query against the 2020-25 holdout.

Forward record

No forward record. Shadow tracking starts after the vault and counts only races run after the freeze.

Lineage

Agent runs

• investigator v1ok · 37s · 16 Oct, 15:44

  Output (schema-checked)

  {
    "reflection": "This thread has one measured idea: the favourite at 5/1 or bigger (sp_decimal >= 6) in a handicap of 14 or more runners. In the earlier research it scored A/E 1.135 on 1,086 bets, and all three periods were above 1 (1.16 on 524, 1.08 on 433, 1.23 on 129). It is published as a live system, so its forward record is the real test. Two things in the numbers limit what we can claim. First, the returns differ by price type: about -9.6% at SP but +16.6% at BSP. The edge exists at exchange prices and the SP margin wipes it out, so the system is only playable on the exchange. Second, the proposed mechanism is not yet separated from a simpler rival. Big-field handicaps carry a heavy overround that bookmakers load onto the outsiders, so the shortest-priced runners may beat their prices whether or not they are favourite. If that is the cause, 'favourite status' is incidental and the second favourite at the same price should also beat its price. The next steps are to test that rival, and to test whether the same consensus effect appears in big-field non-handicaps. The rule should not be sliced further on price or field size.",
    "answers": [],
    "questions": [
      {
        "question": "Is the lift specific to the favourite, or do all short-end runners at 5/1+ in big-field handicaps beat their prices (an overround or price-band effect)?",
        "rationale": "Compare same-race runners at the same price with sp_rank = 2 or 3 against sp_rank = 1. Columns: sp_rank, sp_decimal, field_size, is_handicap, book_pct, favourite_sp. If second favourites at 6.0+ score the same, the mechanism is overround distribution, not market consensus.",
        "observation_ids": [
          "O-a934fc73"
        ],
        "priority": 0.7
      },
      {
        "question": "Does the market-consensus effect also hold for favourites at 5/1+ in big-field non-handicaps (maidens, novice races)?",
        "rationale": "If being the one horse the market settled on is informative in itself, it should not need a handicap. Columns: is_handicap, is_favourite, sp_decimal, field_size, is_maiden, is_novice, race_type.",
        "observation_ids": [
          "O-a934fc73"
        ],
        "priority": 0.5
      },
      {
        "question": "Is the gap between SP and BSP returns (-9.6% vs +16.6%) wider for this selection than for other favourites at the same price?",
        "rationale": "This decides whether the system can be played at SP or only on the exchange. The columns are book_pct, sp_decimal and field_size; BSP itself is post-race and can only be used to measure, never to select.",
        "observation_ids": [
          "O-a934fc73"
        ],
        "priority": 0.4
      }
    ],
    "hypotheses": [
      {
        "title": "Rival: second favourites at 5/1+ in big handicaps also beat their price (overround effect, not favourite status)",
        "family": "race-betting",
        "operator": "rival-explanation",
        "question_id": null,
        "new_question": 0,
        "parent_id": "H199-favourite-at-a-big-price-in-a-big-handicap",
        "reasoning": {
          "observation_ids": [
            "O-a934fc73"
          ],
          "question": "Is the H199 lift caused by favourite status, or by where big-field handicap prices sit in a heavily overround book?",
          "mechanism": "In 14+ runner handicaps the overround is loaded onto outsiders, so the front of the market is relatively generous. The second favourite at 6.0+ sits in the same part of the book as the favourite, so if overround is the cause it gets the same advantage.",
          "market_miss": "Bookmakers spread their margin unevenly across the field, and A/E measured against prices normalised for the whole book credits the shortest runners. Nothing in the form book shows this.",
          "prediction": {
            "direction": "positive",
            "size": "A/E 1.06 to 1.12 on 1000+ bets if the rival holds",
            "falsified_if": "Second favourites score A/E 1.00 or below, which would leave favourite status as the active ingredient"
          },
          "rule_sketch": "is_handicap = 1 AND sp_rank = 2 AND sp_decimal >= 6 AND field_size >= 14"
        },
        "confounders": [
          "joint favourites sharing sp_rank",
          "overall favourite-longshot bias",
          "festival handicaps"
        ],
        "expected_survival": 0.35
      },
      {
        "title": "Generalise: favourites at 5/1+ in big-field non-handicaps beat their price",
        "family": "race-betting",
        "operator": "generalise",
        "question_id": null,
        "new_question": 1,
        "parent_id": "H199-favourite-at-a-big-price-in-a-big-handicap",
        "reasoning": {
          "observation_ids": [
            "O-a934fc73"
          ],
          "question": "Does market consensus on one horse in an open, big field carry information outside handicaps?",
          "mechanism": "When a large, open field has an unusually long-priced favourite, that horse still attracted the most money. That money is informed (yard and market confidence), and it is worth more than the price, which is set by comparison with typical 5/1 shots.",
          "market_miss": "A 5/1+ favourite looks unconvincing, and the price is anchored to how ordinary 5/1 shots perform, most of which are third to fifth choice.",
          "prediction": {
            "direction": "positive",
            "size": "A/E 1.05 to 1.12 on 400+ bets",
            "falsified_if": "A/E 1.00 or below on 300+ bets"
          },
          "rule_sketch": "is_handicap = 0 AND is_favourite = 1 AND sp_decimal >= 6 AND field_size >= 12"
        },
        "confounders": [
          "unraced debutants in maidens",
          "Irish maiden hurdles with big yards",
          "small number of qualifying races"
        ],
        "expected_survival": 0.3
      }
    ],
    "findings": [
      {
        "statement": "H199's edge exists only at exchange prices. It returned +16.6% at BSP but -9.6% at SP on 1,086 bets, so the live system has to be judged and staked at BSP.",
        "kind": "data",
        "observation_ids": [
          "O-a934fc73"
        ]
      },
      {
        "statement": "H199's A/E was above 1 in all three periods (1.16, 1.08, 1.23), but the latest period has only 129 bets, so recent support is thin.",
        "kind": "method",
        "observation_ids": [
          "O-a934fc73"
        ]
      }
    ]
  }

Timeline

1. hypothesis note H199-favourite-at-a-big-price-in-a-big-handicap

   15 Oct, 23:10 · importer

2. H199-favourite-at-a-big-price-in-a-big-handicap Discovery → PROMISING import: tier B: interesting, unproven; best [broad] GREEN A/E 1.135 on 1086 bets (broad GREEN)

   15 Oct, 23:10 · importer

3. import result for H199-favourite-at-a-big-price-in-a-big-handicap (sole favourite): info

   15 Oct, 23:10 · importer

4. import result for H199-favourite-at-a-big-price-in-a-big-handicap (jumps): info

   15 Oct, 23:10 · importer

5. import result for H199-favourite-at-a-big-price-in-a-big-handicap (Flat): info

   15 Oct, 23:10 · importer

6. import result for H199-favourite-at-a-big-price-in-a-big-handicap (broad): info

   15 Oct, 23:10 · importer

7. New idea H199-favourite-at-a-big-price-in-a-big-handicap: H199: favourite at a big price in a big handicap (import)

   15 Oct, 23:10 · importer

Every change is an event with an actor: an agent and its version, an engine, a human, or the importer. Current stage: Promising.