This paper presents a test data compression scheme that can be used to further improve compressions achieved by linear-feedback shift register (LFSR) reseeding. The proposed compression technique can be implemented with very low hardware overhead. The test data to be stored in the automatic test equipment (ATE) memory are much smaller than that for previously published schemes, and the number of test patterns that need to be generated is smaller than other weighted random pattern testing schemes. The proposed technique can be extended to generate test patterns that achieve high n-detection fault coverage. This technique compresses a regular 1-detection test cube set instead of an n-detection test cube set, which is typically n times larger. Hence, the volume of compressed test data for n-detection test is comparable to that for 1-detection test. Experimental results on a large industry design show that over 1600X compression is achievable by the proposed scheme with the test sequence length, which is comparable to that of highly compacted deterministic patterns. Experimental results on n -detection test show that test patterns generated by the proposed decompressor can achieve very high 5-detection stuck-at fault coverage and high compression for large benchmark circuits.