Full Idea
Some entailments do not suffice for supervenience. Being a brother entails being a sibling, but being a sibling does not supervene on being a brother. Sarah has a sister and Jack in an only child. Sarah, unlike Jack, is a sibling; neither is a brother.
Gist of Idea
Some entailments do not involve supervenience, as when brotherhood entails siblinghood
Source
Karen Bennett (Supervenience [2011], §3.2)
Book Reference
'Stanford Online Encyclopaedia of Philosophy', ed/tr. Stanford University [plato.stanford.edu], p.7
A Reaction
The whole point of supervenience, I take it, is to label a relation of tracking, while offering no explanation of the tracking. Entailment would be a rather powerful explanation, as would a dog's being tied to a cart.
Related Idea
Idea 16045 General facts supervene on particular facts, but cannot be inferred from them [Russell, by Bennett,K]