Table 1. Similarity coefficients studied.
| Coefficients | Similarity expression | Source |
|---|---|---|
| 1.Simple matching (SM) |
a + d a + b + c + d |
Sokal and Michener, 1958 |
| 5. Jaccard (J) |
a a + b + c |
Jaccard, 1901 |
| 6. Sorensen-Dice (SD) |
2a 2a + b + c |
Sorensen, 1948; Dice, 1945 |