Validators are selected and assigned to parachains by the randomized Validator Assignment routine. Let's look at this snapshot of parachain validation on https://polkadot.js.org/apps/#/parachains

At the time of writing this response, there are 28 parachains that are assigned 5 validators each. That would be 140 para validators in this era. The remaining (297 - 140 = 157) validators in the active set will only participate in the relay chain block production and finality.

Proof of Validity (PoV) check on parachain blocks is computationally more intensive. Hence, for that work, para validators earn more era points, resulting in an uptick in the earned rewards.

As more parachains run on Polkadot, more validators will take part in para validation. If you are interested in learning about the validation protocol, please refer to this protocol overview document.

Validators are selected and assigned to parachains by the randomized Validator Assignment routine on-chain. Let's look at this snapshot of parachain validation on https://polkadot.js.org/apps/#/parachains

At the time of writing this response, there are 28 parachains that are assigned 5 validators each. That would be 140 para validators in this era. The remaining (297 - 140 = 157) validators in the active set will only participate in the relay chain block production and finality.

Proof of Validity (PoV) check on parachain blocks is computationally more intensive. Hence, for that work, para validators earn more era points, resulting in an uptick in the earned rewards.

As more parachains run on Polkadot, more validators will take part in para validation. If you are interested in learning about the validation protocol, please refer to this protocol overview document.