U.S. flag

An official website of the United States government, Department of Justice.

DNA - A Prosecutor’s Practice Notebook Inventory

Error Rates

Home  |  Glossary  |  Resources  |  Help  |  Contact Us  |  Course Map

The defense may argue that the DNA typing results are not reliable because:

  1. The statistical calculation did not include an error rate to compensate for typing mistakes
  2. The lab protocols are inadequate to reduce the risk of error entirely
  3. The lab as a whole or the individual analyst failed to adhere to the stated protocols
  4. The lab as a whole or the individual analyst failed the proficiency testing

First, the possibility of error goes to the weight, not to the admissibility of the evidence.  Second, the National Academy of Science convened the National Research Council a second time (NRC II) to specifically address in part the issue of whether or not error rates should be included in the statistical calculations used to interpret the results of forensic DNA testing. The NRC II recommended against the use of error rates because there is no simple equation to translate all the possible variables, e.g., number of samples, redundancy in typing, or DNA analyst proficiency into the probability that a reported match is false.

Back Forward