  In this note, we discuss the effective mass of quasiparticles in finite sized
$\nu = 1/2$ systems in the lowest Landau level, given a natural notion we have
of the Fermi surface in these finite sized systems. The effective mass is
related to the difference between instantaneous density-density response
functions of the ground state and excited states of the system; we do a finite
size calculation for this difference for $\nu = 1/2$ systems with 7, 8 and 9
fermions, and conjecture how the difference must look in the thermodynamic
limit.
