Table 3.

Contingency table test set per contact moment

Smoking status	Reference
	Current smoker	Former smoker	Never smoker	No information	Total
Data mining algorithm
Current smoker	576	93	30	23	722
Former smoker	71	265	19	4	359
Never smoker	2	18	230	0	250
Not classified	87	38	28	76 645	76 798
Total	736	414	307	76 672	78 129

Current smoker: precision = 79.7% (95% CI 76.6–82.6%), recall = 78.3% (95% CI 75.1–81.2%), F1-score = 0.79. Former smoker: precision = 73.8% (95% CI 68.9–78.2%), recall = 64.0% (95% CI 59.2–68.6%), F1-score = 0.69. Never smoker: precision = 92.0% (95% CI 87.7–94.9%), recall = 74.9% (95% CI 69.6–79.6%), F1-score = 0.83. Named Entity Recognition of keywords associated with smoking: precision = 98.0% (95% CI 97.1–98.7%), recall = 89.5% (95% CI 87.8–91.0%), F1-score = 0.94.