During the last seven years an extensive confinement database has been assembled on JET of steady state ELMy H-mode plasmas. The database was started under the JET Joint Undertaking and has been continued under EFDA with the addition of a further 200 pulses. In this paper the database is used to assess the effect of three parameters upon the energy confinement, these are the triangularity d, the proximity of the density to the Greenwald density limit and the peaking of the density profile. There is clear evidence from single parameter scans that these three variables do influence the confinement, however the present scaling expression, used to predict the performance of ITER, namely IPB98(y,2)(1), does not contain these variables.