In surveying an area as amorphous as simplified inelastic analysis methods@ a systematic approach is advised. The choice of the system should be designed to provide guidance to the investigator. The approach taken here is based partly upon failure mode classification@ in concert with the underlying theme of the ASME Boiler and Pressure Vessel Code. The classifications of failure can be described in terms of mechanistic observations@ in order to focus attention on the quantities that are to be measured or calculated. For example@ time-dependent and time-independent structural instability calculations involve large deformation and@ although the general complexity can be greatly reduced in any number of ways@ the ability to treat geometric nonlinearity is desirable. Creep-rupture life can be conservatively estimated for some structures through elastic analysis; those structures for which such estimation is not possible@ because of a design feature that prevents the redistribution of stress@ can sometimes be redesigned to alleviate this difficulty. Other designs may not be amenable to this simplified treatment. Creep-fatigue interaction and strain accumulation@ because of the necessity of establishing inelastic strain ranges and cyclic additions@ also lie in the intermediate regime where one is less certain of the advantages of simplified methods.