burnout-tracker / src /error_analysis.py
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import numpy as np
import pandas as pd
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
import sys, os
sys.path.insert(0, '.')
os.makedirs('docs', exist_ok=True)
from xgboost import XGBClassifier
from sklearn.metrics import confusion_matrix, classification_report
from data.data_loader import load_data, preprocess, split_and_scale
from src.smote import smote
from src.hyperparameter_tuning import grid_search
from src.preprocessing_experiment import find_best_threshold
def run_error_analysis():
df = load_data()
X, y, feature_cols = preprocess(df, use_domain_cleaning=True)
X_train, X_val, X_test, y_train, y_val, y_test, _ = split_and_scale(X, y)
X_train_s, y_train_s = smote(X_train, y_train, random_state=42)
best_alpha, best_lambda = grid_search()
model = XGBClassifier(
n_estimators=100, max_depth=4, learning_rate=0.05,
subsample=0.7, colsample_bytree=0.7, min_child_weight=5,
reg_alpha=best_alpha, reg_lambda=best_lambda,
eval_metric='logloss', early_stopping_rounds=15, random_state=42,
)
model.fit(X_train_s, y_train_s, eval_set=[(X_val, y_val)], verbose=False)
val_proba = model.predict_proba(X_val)[:, 1]
threshold, _ = find_best_threshold(y_val, val_proba)
proba = model.predict_proba(X_test)[:, 1]
preds = (proba >= threshold).astype(int)
test_df = pd.DataFrame(X_test, columns=feature_cols)
test_df['true'] = y_test.values
test_df['pred'] = preds
test_df['proba'] = proba
fn = test_df[(test_df['true']==1) & (test_df['pred']==0)] # missed burnout
fp = test_df[(test_df['true']==0) & (test_df['pred']==1)] # wrong alarm
tp = test_df[(test_df['true']==1) & (test_df['pred']==1)] # correctly caught
correct = test_df[test_df['true'] == test_df['pred']]
cm = confusion_matrix(y_test, preds)
# exclude composite features — compare only raw inputs
base_feats = [c for c in feature_cols if c not in
['RECOVERY_SCORE','SOCIAL_SUPPORT_SCORE','LIFESTYLE_SCORE','HEALTH_HABITS']]
diff = (fn[base_feats].mean() - tp[base_feats].mean()).abs().sort_values(ascending=False)
hard_feats = diff.head(6).index.tolist()
margin = 0.10
borderline = test_df[(test_df['proba'] >= threshold-margin) &
(test_df['proba'] <= threshold+margin)]
confident = test_df[~test_df.index.isin(borderline.index)]
border_acc = (borderline['true'] == borderline['pred']).mean()
confid_acc = (confident['true'] == confident['pred']).mean()
print(f"Threshold: {threshold:.2f} | FN: {len(fn)} | FP: {len(fp)}")
print(classification_report(y_test, preds, target_names=['Low Risk','High Risk']))
fig, axes = plt.subplots(2, 2, figsize=(14, 10))
fig.suptitle(
f'Error Analysis — Burnout Risk Classifier\n'
f'Threshold={threshold:.2f} | Test n={len(test_df)} | '
f'FN={len(fn)} (missed burnout) FP={len(fp)} (wrong alarm)',
fontsize=12, fontweight='bold'
)
# ① confusion matrix
ax = axes[0, 0]
im = ax.imshow(cm, cmap='Blues')
ax.set_title('① Failure Counts\nConfusion matrix at tuned threshold', fontweight='bold')
ax.set_xticks([0,1]); ax.set_yticks([0,1])
ax.set_xticklabels(['Predicted\nLow Risk', 'Predicted\nHigh Risk'], fontsize=9)
ax.set_yticklabels(['Actual\nLow Risk', 'Actual\nHigh Risk'], fontsize=9)
cell_labels = [[f'TN\n{cm[0,0]}', f'FP\n{cm[0,1]}\n(wrong alarm)'],
[f'FN\n{cm[1,0]}\n(missed)', f'TP\n{cm[1,1]}']]
for i in range(2):
for j in range(2):
color = 'white' if cm[i,j] > cm.max()/2 else 'black'
ax.text(j, i, cell_labels[i][j], ha='center', va='center',
color=color, fontsize=11, fontweight='bold')
plt.colorbar(im, ax=ax, fraction=0.04)
# ② probability distributions
ax = axes[0, 1]
ax.set_title('② Why the Model Fails\nBoth error types cluster near the decision boundary',
fontweight='bold')
ax.hist(correct['proba'], bins=30, alpha=0.4, color='#2ecc71', label=f'Correct (n={len(correct)})')
ax.hist(fn['proba'], bins=20, alpha=0.8, color='#e74c3c', label=f'False Negative — missed burnout (n={len(fn)})')
ax.hist(fp['proba'], bins=20, alpha=0.8, color='#e67e22', label=f'False Positive — wrong alarm (n={len(fp)})')
ax.axvline(threshold, color='black', linewidth=2, linestyle='--',
label=f'Decision threshold = {threshold:.2f}')
ax.set_xlabel('Predicted Probability of High Burnout Risk')
ax.set_ylabel('Count')
ax.legend(fontsize=8)
ax.annotate('Errors concentrate\nhere — model is\nuncertain, not\nsystematically wrong',
xy=(threshold, ax.get_ylim()[1]*0.6),
xytext=(threshold+0.12, ax.get_ylim()[1]*0.75),
arrowprops=dict(arrowstyle='->', color='black'),
fontsize=8, color='black',
bbox=dict(boxstyle='round,pad=0.3', facecolor='lightyellow', alpha=0.8))
# ③ feature profiles: FN vs TP
ax = axes[1, 0]
ax.set_title('③ Most Challenging Input Types\n'
'Features where missed cases differ most from correctly caught cases',
fontweight='bold')
x = np.arange(len(hard_feats))
w = 0.35
ax.bar(x-w/2, fn[base_feats].mean()[hard_feats], w,
label='False Negatives — missed burnout', color='#e74c3c', alpha=0.85)
ax.bar(x+w/2, tp[base_feats].mean()[hard_feats], w,
label='True Positives — correctly caught', color='#2ecc71', alpha=0.85)
ax.set_xticks(x)
ax.set_xticklabels([f.replace('_','\n') for f in hard_feats], fontsize=8)
ax.set_ylabel('Mean value (standardised)')
ax.axhline(0, color='grey', linewidth=0.8, linestyle='--')
ax.legend(fontsize=8)
largest_gap_idx = int(np.argmax(
np.abs(fn[base_feats].mean()[hard_feats].values -
tp[base_feats].mean()[hard_feats].values)
))
ax.annotate('Largest\ndifference',
xy=(largest_gap_idx, fn[base_feats].mean()[hard_feats].iloc[largest_gap_idx]),
xytext=(largest_gap_idx+0.6,
fn[base_feats].mean()[hard_feats].iloc[largest_gap_idx]+0.3),
arrowprops=dict(arrowstyle='->', color='black'),
fontsize=8,
bbox=dict(boxstyle='round,pad=0.3', facecolor='lightyellow', alpha=0.8))
# ④ borderline vs confident accuracy
ax = axes[1, 1]
ax.set_title('④ Hardest Input Zone\nAccuracy collapses near the decision boundary',
fontweight='bold')
groups = [f'Borderline\n(within ±{margin} of threshold)\nn={len(borderline)}',
f'Confident\n(outside ±{margin})\nn={len(confident)}']
accs = [border_acc, confid_acc]
bars = ax.bar(groups, accs, color=['#e67e22','#3498db'], alpha=0.85, width=0.4)
ax.set_ylim(0, 1.05)
ax.set_ylabel('Accuracy')
ax.axhline(0.5, color='grey', linestyle='--', linewidth=1, label='Random chance')
for bar, acc in zip(bars, accs):
ax.text(bar.get_x() + bar.get_width()/2, acc + 0.03,
f'{acc:.1%}', ha='center', fontsize=13, fontweight='bold')
gap = confid_acc - border_acc
ax.annotate(f'{gap:.1%} accuracy gap\n→ errors are not random;\nthey concentrate where\nthe model is uncertain',
xy=(0, border_acc), xytext=(0.55, border_acc - 0.18),
arrowprops=dict(arrowstyle='->', color='black'),
fontsize=8.5,
bbox=dict(boxstyle='round,pad=0.3', facecolor='lightyellow', alpha=0.8))
ax.legend(fontsize=8)
plt.tight_layout()
plt.savefig('docs/error_analysis.png', dpi=150, bbox_inches='tight')
plt.close()
print(f"\nSaved docs/error_analysis.png")
print(f"\nKey findings:")
print(f" Borderline accuracy : {border_acc:.1%} vs Confident accuracy: {confid_acc:.1%}")
print(f" Hardest feature : {hard_feats[0]} (gap = {diff.iloc[0]:.3f})")
print(f" FN > FP : {len(fn) > len(fp)} — model leans toward false alarms over misses")
if __name__ == '__main__':
run_error_analysis()