In 154 of the DNA exonerations, invalid or improper forensic testing and testimony played a part in the conviction. We have been able to use modern advancements in DNA to take a more critical look at the now out-dated forensic tools used to convict thousands of people around the United States and the globe. There have been significant developments in ballistics, fingerprinting, arson, shaken baby syndrome, microscopic hair comparison, and many others. Before DNA, we used serology, blood typing, or microscopic hair comparison to try to help us figure out who committed the crime. As we know now, that testing is not very discriminatory and, compared to what we can do now with DNA, not very useful.