Liquidity:

Current USD value of assets locked in the pool.

Volume:

Total value of assets swapped in the pool over the last 24 hours.

Fees:

Estimated by taking the average daily fees for the previous 30 days with a 2x weighting for the last 7 days.

Impermanent Loss:

Estimated by taking the average price ratio divergence for the last 30 days and plugging it into the IL curve found here.

Sushi Rewards:

Calculated using the current Sushi emission rate for the given pool, the price of Sushi, and the amount of liquidity staked in the Masterchef contract. The full calculation is described here.

ROI:

The ROI is simply the combination of fees, impermanent loss, and liquidity mining rewards. Note: ROI is with respect to the LP Tokens (50% exposed to price of ETH and 50% exposed to another asset). I would strongly recommend reading this section to understand exactly what this percentage means.