Differences
This shows you the differences between two versions of the page.
| Both sides previous revisionPrevious revisionNext revision | Previous revision | ||
| data_mining:error_analysis [2018/05/21 19:45] – [Working on most promising problems] phreazer | data_mining:error_analysis [2018/05/21 22:24] (current) – [Problems with different train and dev/test set dist] phreazer | ||
|---|---|---|---|
| Line 139: | Line 139: | ||
| Principles when fixing labels: | Principles when fixing labels: | ||
| - | - Apply same process to dev and test set (same distribution) | + | * Apply same process to dev and test set (same distribution) |
| - | - Also see what examples algo got right (not only wrong) | + | |
| - | - Train and dev/test data may come from different distribution (no problem if slightly different) | + | |
| + | |||
| + | ====== Missmatched train and dev/test set ====== | ||
| + | |||
| + | * 200.000 high qual pics | ||
| + | * 10.000 low qual blurry pics | ||
| + | |||
| + | * Option 1: Combine images, random shuffle in train/ | ||
| + | * Advantage: Same distribution | ||
| + | * Disadvantage: | ||
| + | * Option 2: | ||
| + | * Train set: 205.000 with high and low qual; Dev & Test: 2500 low quality | ||
| + | * Advantage: Optimizing right data | ||
| + | * Disadvantage: | ||
| + | |||
| + | ====== Problems with different train and dev/test set dist ====== | ||
| + | |||
| + | Not always good idea to use different dist in train and dev | ||
| + | |||
| + | * Human error ~ 0 | ||
| + | * Train 1% | ||
| + | * Dev 10% | ||
| + | |||
| + | Training-dev set: same distribution as training set, but not used for training | ||
| + | |||
| + | * Train 1% | ||
| + | * Train-dev: 9% | ||
| + | * Dev: 10% | ||
| + | |||
| + | Still high gap between train and train-dev => variance problem | ||
| + | |||
| + | If Train and Train-dev would be closer => data-mismatch problem. | ||
| + | |||
| + | Summary: | ||
| + | * Human level 4% | ||
| + | * Avoidable bias | ||
| + | * Train 7% | ||
| + | * Variance | ||
| + | * Train-dev: 10% | ||
| + | * Data mismatch | ||
| + | * Dev: 12% | ||
| + | * Degree of overfitting to dev set (if to high => bigger dev set) | ||
| + | * Test: 12% | ||
| + | |||
| + | ====== Data mismatch problems ====== | ||
| + | |||
| + | * Error analysis to understand difference between training and dev/test set | ||
| + | * Make training more similar / collect more data similar to dev/test set (e.g. simulate audio environment) | ||
| + | * Artificial data synthesis | ||
| + | * Problems: Possible that sampling from too few data (for human it might appear ok) | ||