The assessment of JET magnetics has been carried out using a statistical technique on a large set of sensor data. The results highlight that improved accuracy in the magnetic field reconstruction can be obtained by making an efficient use of the information brought in by the available sensors, in conjunction with the new magnetics that will be installed during the 2004 shutdown (JET Enhancement on Magnetic Diagnostics). Moreover, the better estimation of the magnetic configuration provides an improved capability to locate the plasma boundary and determine its shape.