# Amazon Reviews 2023 — Processed Dataset Statistics

Protocol: official rating_only -> iterative **5-core** -> **leave-one-out** split -> sequential history at maxlen **20 & 50** -> item metadata join. All outputs are **JSONL**.

| Category | #Users | #Items | #Interactions | Avg len | Median | Sparsity | Items w/ meta |
|----------|-------:|-------:|--------------:|--------:|-------:|---------:|--------------:|
| Video_Games | 94,762 | 25,612 | 814,586 | 8.5961 | 6 | 0.99966437 | 25,612 (100%) |
| Industrial_and_Scientific | 50,985 | 25,848 | 412,947 | 8.0994 | 6 | 0.99968665 | 25,848 (100%) |
| Beauty_and_Personal_Care | 729,576 | 207,649 | 6,624,441 | 9.0799 | 7 | 0.99995627 | 207,649 (100%) |
| Musical_Instruments | 57,439 | 24,587 | 511,836 | 8.9109 | 7 | 0.99963757 | 24,587 (100%) |
| Books | 776,370 | 495,063 | 9,488,297 | 12.2214 | 7 | 0.99997531 | 495,063 (100%) |

## Leave-one-out split row counts

| Category | direct train | valid | test | seq20 train | seq50 train |
|----------|-------------:|------:|-----:|------------:|------------:|
| Video_Games | 625,062 | 94,762 | 94,762 | 530,300 | 530,300 |
| Industrial_and_Scientific | 310,977 | 50,985 | 50,985 | 259,992 | 259,992 |
| Beauty_and_Personal_Care | 5,165,289 | 729,576 | 729,576 | 4,435,713 | 4,435,713 |
| Musical_Instruments | 396,958 | 57,439 | 57,439 | 339,519 | 339,519 |
| Books | 7,935,557 | 776,370 | 776,370 | 7,159,187 | 7,159,187 |

## Validation vs official 5-core

| Category | my 5core | official | match | my #test | official #test | match |
|----------|---------:|---------:|:-----:|---------:|---------------:|:-----:|
| Video_Games | 814,586 | 814,586 | OK | 94,762 | 94,762 | OK |
| Industrial_and_Scientific | 412,947 | 412,947 | OK | 50,985 | 50,985 | OK |
| Beauty_and_Personal_Care | 6,624,441 | 6,624,441 | OK | 729,576 | 729,576 | OK |
| Musical_Instruments | 511,836 | 511,836 | OK | 57,439 | 57,439 | OK |
| Books | 9,488,297 | 9,488,297 | OK | 776,370 | 776,370 | OK |