2020 Census Redistricting Noisy Measurement File (NMF)

JUNE 15, 2023 - The U.S. Census Bureau today released the Noisy Measurement File for the 2020 Census Production Settings Redistricting Data (P.L. 94-171). This is a specialized file designed to give researchers the opportunity to independently process and assess the impact of the 2020 Census disclosure avoidance system's TopDown Algorithm (TDA) on the redistricting data.  

Noisy measurement files (NMFs) are the intermediate output of the TDA, prior to the post-processing that ensure internal and hierarchical consistency. The TDA generates noisy measurements when it applies differentially private noise to each of the tabulations from the confidential data. Because the noise can result in internal and hierarchical inconsistencies in the tables we publish, the TDA completes a final step called "post-processing." That post-processing improves accuracy for lower-level geographies and corrects those inconsistencies before tables are published. 

The Census Bureau is providing guidance and tools for researchers interested in using the NMFs to generate unbiased estimates and confidence intervals for the data, including an online technical workshop today at 3:00 p.m. EDT. The recording, transcript and slides will be available following today's workshop.

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