**How to calculate the similarity of an asymmetric binary variable using Jaccard coefficient****?**

# There are many methods to calculate the similarity of data. Jaccard coefficient is one of them.

# Jaccard coefficient is used to calculate the similarity among asymmetric binary attributes.

**Contingency table for binary data:**

Object 2 |
||||

Object 1 |
1 / True / Positive | 0 / False / Negative | Sum | |

1 / True / Positive | A | B | A + B | |

0 / False / Negative | C | D | C + D | |

Sum | A + C | B + D |

In table 1 we can consider the following facts.

A represents that object 1 is True and object 2 is also True.

B represents that object 1 is True and object 2 is False.

C represents that object 1 is False and object 2 is True.

D represents that object 1 is False and object 2 is also False.

Name |
Fever |
Cough |
Test 1 |
Test 2 |
Test 3 |
Test 4 |

Asad | Negative | Yes | Negative | Positive | Negative | Negative |

Bilal | Negative | Yes | Negative | Positive | Positive | Negative |

Tahir | Positive | Yes | Negative | Negative | Negative | Negative |

In table 2, Asad, Bilal and Tahir are objects. Negative values represents False and Positive represents Negative.

**Consider 1 for positive/True and 0 for negative/False.**

Similarly, we can calculate the similarity of one object with each other object.