This NIJ solicitation extends prior NIJ work to improve the understanding of the accuracy, reliability, and measurement validity of forensic science disciplines. NIJ is interested in research that focuses on expanding the scientific basis of forensic methods, as well as the development of quantifiable measures of the reliability and accuracy of forensic analyses. In the past, NIJ has encouraged applicants to propose new approaches to these problems, including quantification of methods that are currently qualitative in nature. NIJ is also interested in developing an understanding of human factors that may affect forensic analyses. Similar to professionals in other fields, forensic scientists may be subject to human observer bias, whether it is related to contextual bias, perceptual errors, or other factors.