Young horses in 3m+ handicap hurdles beat their price as marathon chasers do

Reasoning

Why this hypothesis exists: what the lab saw, the question it asked, the mechanism it proposed, what it predicted, and the result that would prove it wrong. Written before the test was run.

1. Observed
   • H-b9326edc (Older higher-weighted marathon chasers match the young: weight positio) was predicted positive but the vault years went the other way: A/E 0.9 on 1129 bets. O-7d4a82d7
   • H-8810c1c1 (Rival: short-priced runners of all ages beat their SP in marathon hand): the price band 'up to 7/1' carries the effect (A/E 1.33) while the rest score up to 3/1 0.95. O-ee5d9dfa
2. AskedAre older (8+) runners more than 7 lb above bottom weight in 3m4f+ handicap chases mildly over-bet, the mirror of the young lift, given their 0.90 on 1129 in the vault? testing
3. MechanismYoung horses are still building stamina and the market treats them as unproven at the longest trips of each code. The ones running there are often progressive stayers, and their price may not reflect it.
4. Why the market misses itOlder runners show proven stamina in the form book, so the money goes to them. Young horses carry the doubt in their price.
5. Predictedpositive, A/E 1.05 to 1.12 on 500+ bets
6. Falsified ifA/E at or below 1.0 on 400+ bets
7. Rule sketchrace_type = 'Hurdle' AND is_handicap = 1 AND age <= 6 AND distance_yards >= 5940

Mechanism and rationale

Young horses are still building stamina and the market treats them as unproven at the longest trips of each code. The ones running there are often progressive stayers, and their price may not reflect it.

The rule

race_type = 'Hurdle' AND is_handicap = 1 AND age <= 6 AND distance_yards >= 5280

Reads: race_type, is_handicap, age, distance_yards

Pre-registration

Spec hash (sha256 of the canonical pre-spec)

bd85b929ef2dc78dd1bda1dbd976287df79bf70f2546fa379313fa27227636f7

Frozen

not frozen

The definition can still change.

Confounders

• field_size: big-field staying handicaps (festival-type races) may carry the lift on their own, as a rival in the chase analogue suggested
• race_class: young progressive stayers may cluster in higher-class handicaps where the prices are more efficient, or in low-class ones where they are not
• going_group: soft-ground 3m hurdles are a stamina test that may favour or punish young horses whatever the market thinks
• prior_runs: lightly raced young horses may carry an unexposed-handicap-mark effect that has nothing to do with stamina
• weight position (weight_lbs relative to bottom_weight_lbs): in marathon chases the weight split mattered more than age in discovery but failed in the vault, so check it here and do not slice on it
• price band concentration: earlier positive marathon slices leaned on narrow price bands (4/1 to 7/1, or 16/1+), so check the lift across bands
• novice/maiden status: young horses in long novice hurdles were over-bet (H171, A/E 0.87), so separate handicap from novice context
• region: GB and IRE staying handicap hurdles may price youth differently

Discovery result

fail broad rule · 16 Oct, 14:35

Bets

772

89 winners

A/E

0.94

95%: 0.76 to 1.16

SP return

-30.0%

level stakes

Betfair SP return

-12.0%

760 bets with a BSP

Strike rate 11.5%. p = 0.72. Same-race control: the other runners in these races had A/E 1.06, so the selection did not beat its own races. Zone: discovery. Evaluator eval-1.0, data 6a4e98be18e83933

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

• designer v1ok · 37s · 16 Oct, 14:34

  Output (schema-checked)

  {
    "rule": "race_type = 'Hurdle' AND is_handicap = 1 AND age <= 6 AND distance_yards >= 5280",
    "refinements": [
      {
        "label": "Extreme hurdle trip (3m3f+), the closest analogue to the 3m4f+ marathon chase",
        "rule": "race_type = 'Hurdle' AND is_handicap = 1 AND age <= 6 AND distance_yards >= 5940"
      },
      {
        "label": "14/1 or shorter, because edges at big prices rest on a few longshot wins",
        "rule": "race_type = 'Hurdle' AND is_handicap = 1 AND age <= 6 AND distance_yards >= 5280 AND sp_decimal <= 15"
      }
    ],
    "control": {
      "description": "The other runners in the same races, which are mostly aged 7 and over, should come in at or slightly below par (A/E about 0.93 to 1.0). That would mean the money goes to proven older stayers. If the older runners in the same races also beat their prices, the lift belongs to the race type (for example, overround or longshot structure in staying handicap hurdles) and not to youth. In that case the hypothesis fails. The control rule names the older group in the same race population.",
      "rule": "race_type = 'Hurdle' AND is_handicap = 1 AND age >= 7 AND distance_yards >= 5280"
    },
    "pass_criteria": {
      "min_bets": 300,
      "min_ae": 1.05,
      "max_p": 0.05
    },
    "forward_bar": {
      "min_bets": 150,
      "min_ae": 1,
      "max_p": 0.2
    },
    "confounders": [
      "field_size: big-field staying handicaps (festival-type races) may carry the lift on their own, as a rival in the chase analogue suggested",
      "race_class: young progressive stayers may cluster in higher-class handicaps where the prices are more efficient, or in low-class ones where they are not",
      "going_group: soft-ground 3m hurdles are a stamina test that may favour or punish young horses whatever the market thinks",
      "prior_runs: lightly raced young horses may carry an unexposed-handicap-mark effect that has nothing to do with stamina",
      "weight position (weight_lbs relative to bottom_weight_lbs): in marathon chases the weight split mattered more than age in discovery but failed in the vault, so check it here and do not slice on it",
      "price band concentration: earlier positive marathon slices leaned on narrow price bands (4/1 to 7/1, or 16/1+), so check the lift across bands",
      "novice/maiden status: young horses in long novice hurdles were over-bet (H171, A/E 0.87), so separate handicap from novice context",
      "region: GB and IRE staying handicap hurdles may price youth differently"
    ],
    "mechanism": "Young horses (6 and under) are still building stamina. At the longest trips of either code the market treats them as unproven stayers. The ones whose connections run them in 3m+ handicap hurdles are often progressive stayers that are still improving. Their handicap mark and price lag that improvement. The same mechanism appears to lift young horses in 3m4f+ handicap chases (H175, A/E 1.16 on 618). This hypothesis tests whether it carries over to the longest hurdle trips.",
    "market_miss": "Older runners have proven stamina in the form book (placed or won at 3m+), so punters and odds-compilers lean towards them. A young horse with few or no runs at the trip carries the stamina doubt in its price, even when its profile (progressive, bred to stay, stepping up) points to improvement. The form book cannot yet show what the horse will do over the trip, so the market under-weights its upside.",
    "prediction": {
      "direction": "positive",
      "size": "A/E 1.05 to 1.12 on 500+ bets",
      "falsified_if": "A/E at or below 1.0 on 400+ bets, or a lift of the same size or larger in the older-runner control in the same races, which would mean the lift is a race-type effect and not a youth effect"
    },
    "notes": "Change from the sketch: the sketch used distance_yards >= 5940 (3m3f+), but the title and question say 3m+ (5280 yards). The prediction also needs 500+ bets, which 3m3f+ handicap hurdles are unlikely to supply. The broad rule therefore uses >= 5280. The 3m3f+ cut is kept as refinement 1, because it is the closest structural match to the 3m4f+ marathon chase. min_bets is raised to 300 because two marathon slices that passed on about 300 bets failed in the vault. Age <= 6 (not <= 7 as in chases) reflects the younger age profile of hurdlers."
  }

Timeline

1. Job 1801 finished

   16 Oct, 14:35 · engine:compute-1

2. H-ea366189 Discovery → KILLED fails: A/E 0.945, needs 1.05; p 0.7169, needs 0.05 or lower; periods [0.96, 0.91], each needs 1.0; A/E 0.945 against same-race control 1.062, needs 0.03 above (not a niche pass: A/E 0.945 below 1.05; p 0.7168605784413475 above 0.5; does not beat the same-race control 1.062; a period points the other way [0.96, 0.91])

   16 Oct, 14:35 · engine:evaluator

3. discovery result for H-ea366189 (broad rule): fail

   16 Oct, 14:35 · engine:evaluator

4. H-ea366189 Designed → RESEARCHdiscovery measuring on the discovery zone

   16 Oct, 14:35 · engine:orchestrator

5. compute-1 took job 1801 (evaluate, attempt 1)

   16 Oct, 14:35 · compute-1

6. Job 1799 finished

   16 Oct, 14:34 · engine:ai-1

7. Queued evaluate on the compute lane: discovery run of the broad rule

   16 Oct, 14:34 · engine:scheduler

8. H-ea366189 Proposed → RESEARCHdesigned pre-spec written and hashed

   16 Oct, 14:34 · agent:designer@v1

9. ai-1 took job 1799 (design, attempt 1)

   16 Oct, 14:34 · ai-1

10. Queued design on the ai lane: write the pre-spec

    16 Oct, 14:33 · engine:scheduler

11. New idea H-ea366189: Young horses in 3m+ handicap hurdles beat their price as marathon chasers do (replicate)

    16 Oct, 14:33 · agent:investigator@v1

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