NIST is working toward understanding and improving the accuracy and precision of spatially resolved isotopic and chemical compositional analysis in the atom probe. The development of accurate analytical approaches and reference materials for electrical and thermal conductors and insulators is critical to this program. Quantitative comparison with other bulk and microscopic methods such as 3D electron microscopy and depth profiling with secondary ion mass spectrometry is performed. We are developing an understanding of the specimen material properties and method improvements needed to improve and broaden the applicability of the technology. Improvement to laser and other instrument systems, instrument controls and automation, and modeling approaches are researched and developed. Test structures, reference materials, and modeling programs are developed in collaboration with industry and academia.