A Christmas classification problem

Talking about classification problems with blood-soaked consequences, the Christmas period offers an archetypal classification problem:

The three wise following the star announcing the birth of the new king, stop on their way at their colleague King Herod. Not minding the old king’s feelings, they autistically tell him the “good” news, that a child is born, which is going to take his kingdom.

King Herod, a true politician, keeps his poker face, sends of the three autist on their way to find this new king baby and asks them to stop by on their way back to let him know, where he can find his heir apparent so he too can go to murder to death greet the little fellow.

Anyhow, long story short, kings find the baby, but are warned by an angel to take a different route avoiding further confrontations with Herod.

Herod is left in the dark, but being a laudably proactive type of ruler decides to run a quick search-and-destroy op for the little boy:

Then Herod, when he saw that he was mocked of the wise men, was exceeding wroth, and sent forth, and slew all the children that were in Bethlehem, and in all the coasts thereof, from two years old and under, according to the time which he had diligently inquired of the wise men.

Matthew 2:1-23 (King James Version)

or in more readable format:

kill * where (age<2 & gender='M' & region='Betlehem')

Matthew 2:1-23 (SQL Version)

See, Herod needs to find the baby Jesus, a most important classification problem if there was one, but has only three features to work with: approximate age, gender and rough region. The problem is particularly hard, because there is large class imbalance (new_king=TRUE only for a single tuple, the little Jesus).
He therefore executes a crude classification algorithm (a simple decision tree to be specific) which has a high sensitivity, but abysmal specificity.

Tintoretto: The Massacre of Innocents. And you thought you had a bad Christmas, because you got socks again.

Thus the first Christmas was soaked in babies’ blood and Game of Thrones is a Disney production compared to the Bible.
And that’s this year’s uplifting Christmas story for you!

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