GRAMMAR HALL 4-QUADRANT SPEED–ACCURACY MATRIX & FSRS FORENSICS

Grammar Hall Telemetry Diagnostics & Empirical Error Taxonomy (IELTS Academic)

Every item attempt is classified along accuracy and pace ratio (r = t_actual / t_target) and scheduled via FSRS v4.5 power-law forgetting curves.

Tracked Corpus

26 Empirical Error Classes • 96 Tasks

4-Quadrant Speed–Accuracy Distribution

Pace Ratio Threshold: r = t_elapsed / t_budget = 1.00x

Q1: Fast & Correct (Mastered)

FAST_CORRECT_MASTERED

54% (68 items)

Gate Rule: Correct AND Pace Ratio <= 1.0x

Prescribed Action: Standard FSRS Expansion (Rating = Good/Easy) • +1 Toward Redemption Graduation

Q2: Slow & Correct (Timeout Horizon Risk)

SLOW_CORRECT_DRILL_SPEED

22% (28 items)

Gate Rule: Correct AND Pace Ratio > 1.0x

Prescribed Action: Enters Redemption Bank for 0.85x Speed Compression Drill (Rating = Hard)

Q3: Fast & Wrong (Distractor Trap Susceptible)

FAST_WRONG_TRAP_SUSCEPTIBLE

15% (19 items)

Gate Rule: Incorrect AND Pace Ratio <= 1.0x

Prescribed Action: Immediate Error-Taxonomy Trap Counter-Inoculation + Locked Redemption Entry

Q4: Slow & Wrong (Core Comprehension / Concept Gap)

SLOW_WRONG_CONCEPT_GAP

9% (11 items)

Gate Rule: Incorrect AND Pace Ratio > 1.0x

Prescribed Action: Untimed Discourse & Structural Deconstruction + FSRS Stability Reset (Again)

Attempt CorrectElapsed (s):Target Budget (s):

Pace Ratio: 0.7556xFLUENCY_MASTERY (FSRS: Easy)

REDEMPTION MISTAKE BANK

Redemption Mistake Bank Graduation Counter (2 Consecutive FAST_CORRECT Clears)

Items locked in the Redemption Mistake Bank require 2 consecutive FAST_CORRECT attempts on unseen sibling items to graduate.

Active Bank: 4 Locked Items

IELTS_ACAD_R_P1_Q2LOCKED (1/2 FAST_CORRECT)

Error Trap: ERR_EPISTEMIC_FALSE_VS_NOT_GIVEN

Salicornia bigelovii requires genetic modification before it can absorb sodium ions into cellular vacuoles.

2 consecutive FAST_CORRECT clears required

PTEA_R_MCMA_Q1LOCKED (0/2 FAST_CORRECT)

Error Trap: ERR_PTE_NEGATIVE_MARKING_OVERSELECTION

Which of the following statements are supported by the passage on urban microclimates? (+1/-1 clamped at 0)

2 consecutive FAST_CORRECT clears required

OET_RA_P1_Q3LOCKED (1/2 FAST_CORRECT)

Error Trap: ERR_OET_PART_A_WRONG_CLINICAL_TEXT_OR_TABLE_ROW_LOOKUP

Adjusted oral ciprofloxacin regimen for an adult acute pyelonephritis patient with eGFR 18 mL/min.

2 consecutive FAST_CORRECT clears required

CELPIP_L_P1_Q1LOCKED (1/2 FAST_CORRECT)

Error Trap: ERR_LISTENING_SELF_CORRECTION_PIVOT_TRAP

Which kayak session does the resident decide to register for after the coordinator checks cancellations?

2 consecutive FAST_CORRECT clears required

FSRS v4.5 MEMORY RETENTION CURVE

Power-Law Retrievability R(t, S) = (1 + 19/81 * t/S)^(-0.5)

R(S, S) = 90.0%

Card Stability S (Days for R: 100% → 90%):S = 6.0 days

t = 00d elapsedR = 100.0% (RETAINED)

t = 01d elapsedR = 98.1% (RETAINED)

t = 02d elapsedR = 96.3% (RETAINED)

t = 03d elapsedR = 94.6% (RETAINED)

t = 05d elapsedR = 91.5% (RETAINED)

t = 07d elapsedR = 88.6% (DUE <= 90%)

t = 10d elapsedR = 84.8% (DUE <= 90%)

t = 14d elapsedR = 80.4% (DUE <= 90%)

t = 21d elapsedR = 74.1% (DUE <= 90%)

t = 30d elapsedR = 67.8% (DUE <= 90%)

If Rated Again (1) at t=3d → Next Stability S' = 1.6774d (Interval: 2d)

If Rated Good (3) at t=3d → Next Stability S' = 9.3718d (Interval: 9d)

Top Triggered Empirical Error Taxonomy Traps

Linked to FSRS Concept Cards

ERR_EPISTEMIC_FALSE_VS_NOT_GIVEN

IELTS / CELPIP Reading14 Triggers

Distinguish direct polar contradiction (FALSE/NO) from unstated comparative assertions (NOT GIVEN).

ERR_PTE_NEGATIVE_MARKING_OVERSELECTION

PTE Reading & Listening (MCMA / HIW)11 Triggers

Never select a secondary option in MCMA or HIW unless certainty exceeds 75%; +1/-1 net scoring erodes verified gains.

ERR_OET_PART_A_WRONG_CLINICAL_TEXT_OR_TABLE_ROW_LOOKUP

OET Reading Part A (15m Locked)9 Triggers

Cross-check renal eGFR and paediatric vs. adult dosing rows in Text B before transcribing exact dosage tokens.

ERR_OET_WRITING_IRRELEVANT_CASE_NOTE_INCLUSION

OET Writing (Nursing / Medicine / Pharmacy)8 Triggers

Omit resolved historical surgeries, unrelated family social history, and normal baseline vitals when unrelated to the referral.

ERR_LISTENING_SELF_CORRECTION_PIVOT_TRAP

IELTS / OET / CELPIP Listening7 Triggers

Wait for adversative discourse pivots ("actually", "on second thought", "scratch that") before locking the option.

ERR_PTE_MIC_SILENCE_3S_CUTOFF

PTE Speaking (RA / RS / DI)6 Triggers

Maintain continuous phonation with inter-word pauses strictly below 3,000ms to prevent automatic microphone lock.