### Sibling Rank Percent

The numeric rank of each sibling (items in the same group or category), divided by the total count of siblings. Possible values include decimal values > 0 and <= 1.

Sibling Rank Percent achieves a numeric value which is comparable between groups with different counts of siblings. For example, in a group with 11 items, rank 6 is the middle rank, while in a group of 21 items, the middle rank is 11. While the sibling rank values 6 and 11 are very different numbers, the sibling rank percent value 6/11 = 0.55 and 11/21 = 0.52 are comparable. From both these values, you understand that the item is ranked slightly worse than half of its group peers.

While Sibling Rank assigns the value 1 to the best ranked item, Sibling Rank Percent assigns 1.00 to the worst ranked item.

While Sibling Rank has an unknown upper bound, since it depends on the number of siblings or items, Sibling Rank Percent is always between 0 and 1. The value of the best ranked item approaches zero, but never reaches 0, as the count of siblings grows. For example, rank 1 out of 1 000 000 siblings is a Sibling Rank Percent of 1/1000000, which is greater than 0.

ParentGroup |
Sibling |
Value |
Sibling Rank |
Sibling Rank Percent |

A |
a1 |
17 |
1 |
0.20 |

A |
a2 |
5 |
5 |
1.00 |

A |
a3 |
12 |
2 |
0.40 |

A |
a4 |
6 |
4 |
0.80 |

A |
A5 |
11 |
3 |
0.60 |

B |
b1 |
3 |
4 |
0.80 |

B |
b2 |
8 |
3 |
0.60 |

B |
b3 |
14 |
5 |
0.20 |

B |
b4 |
2 |
1 |
1.00 |

B |
b5 |
9 |
2 |
0.40 |