  We review the extraction of fundamental supersymmetric parameters from
experimental observables related to the detection of charginos and selectrons
at $e^+e^-$ colliders. We consider supergravity models with universal scalar
and gaugino masses and radiatively broken electroweak symmetry. Two scenarios
are considered: (a) The lightest chargino is light enough to be produced at
LEP2, and (b) the right handed selectron is light enough to be produced at
LEP2. We show how the validity of supergravity models can be tested even if
experimental errors are large. Interesting differences between the spectrum in
the two scenarios are pointed out.
