A new form of LFSR reseeding that provides higher encoding efficiency and hence greater reduction in test data storage requirements is described. Previous forms of LFSR reseeding have been static (i.e. test generation is stopped and the seed is loaded at one time) and have required full reseeding (i.e. n=r bits are used for an r-bit LFSR). The new form of LFSR reseeding proposed here is dynamic (i.e. the seed is incrementally modified while test generation proceeds) and allows partial reseeding (i.e. n