A tape drive assembly for data storage on a magnetic tape includes a tape head, a cartridge receiver and a controller. The cartridge receiver selectively receives a cartridge having a test tape formatted at a predetermined location with data errors with predetermined type, size and distribution representative of data errors in tape drives. The test tape is able to measure the quality of heads in suspect tape drives by comparing the ratio of the error count successfully recovered by the suspect head to that recovered by the reference drive while reading the same error distributions.