Generally, how will NIEM promote data sharing among all levels of government and how does it improve on previously-issued standards such as GJXDM?

"The concept behind NIEM and its core data exchange standards are proven, since NIEM has been built upon the Global Justice XML Data Model (GJXDM), which has successfully linked justice and public safety systems over the past three years. Many real world information exchanges such as Suspicious Activity Reporting (SAR) span multiple domains. NIEM extends the public safety and justice standards to support the intelligence, immigration, emergency management, international trade, infrastructure protection, and information assurance domains. Additionally, the NIEM 2.0 release significantly improves on its GJXDM predecessor in several areas including improved cross-domain harmonization of data components, better tools to improve efficiency and reuse, and more precise technical documentation such as the NIEM Naming and Design Rules (NDR).   However, beginning with the recent NIEM 2.0 release, GJXDM has been incorporated as the "justice domain" of NIEM and as such inherits these benefits as well."