SFITTER is a new analysis tool to determine supersymmetric model parameters
from collider measurements. Using the set of supersymmetric mass measurements
at the LC and at the LHC we show how both colliders probe different sectors of
the MSSM Lagrangian. This observation is a strong motivation to move from a
parameter fit assuming a certain model to the unconstrained weak-scale MSSM
Lagrangian. We argue how the technical challenges can be dealt with in a
combined fit/grid approach with full correlations.Comment: contribution to LHC-LC Study Group, G.Weiglein et a