  The bipartite entanglement of a pure quantum state is known to be
characterized by its Schmidt decomposition. In particular the state is
maximally entangled when all the Schmidt coefficients are equal. We point out a
convenient method which always yields a single analytical condition for the
state to be maximally entangled, in terms of its expansion coefficients in any
basis. The method works even when the Schmidt coefficients cannot be calculated
analytically, and does not require their calculation. As an example this
technique is used to derive the Bell basis for a system of two qubits. In a
second example the technique shows a particular state to \textit{never} be
maximally entangled, a general conclusion that cannot be reached using the
Schmidt decomposition.
