Absolutely, but only to an extent--and under specific circumstances. For instance, the Battleship has about 10x the shield, HP, and attack of a frigate. It also has more armor than the frigates have attack--so it'll take more than 10 frigates to start draining the HP from the Battleship. It would be a standoff. The frigate fleet may lose one or two, but they can't hurt the battleship much.
If the Battleship has a heavy equipment loadout, it can inflict greater casualties. But if the frigates are sporting EMP's and torpedos, they can 1) negate the Battleship's main attack, 2) cut its armor in half, and 3) bring actual pain with torpedo hits. Even if the Battleship has several CM's, it'll eventually get hit with the EMP at least a few times.
So to maintain an advantage against larger ships, you'll need a larger number of escorts. As fleets with larger ships grow in number, it'll be more difficult to maintain the necessary lead--although large escort-based fleets will still have potent uses. The balance I'm going for is that massing smaller ships will be more efficient bang for your buck, but larger ships will be a more effective premium investment if properly protected.