A joint FBI, Department of Justice and Innocence Project review found that FBI examiners had overstated the significance of microscopic hair comparison matches in the overwhelming majority of trial testimony and reports reviewed, in cases going back decades, including several that led to convictions later overturned by DNA evidence.
What would resolve this A published statistical error-rate study for microscopic hair comparison under blind proficiency testing, and a documented professional consensus on what conclusion language, if any, the method can support without DNA confirmation.
OpenForensic science standards and trace evidence analysisInnocence Project: FBI Testimony on Microscopic Hair Analysis Review