Understanding Our Estimates of the Unauthorized Immigrant Population: A Methodological Deep Dive
For accurate and insightful analysis of immigration trends, itS crucial to understand how estimates of the unauthorized immigrant population are developed.This document provides a detailed explanation of our methodology, emphasizing the rigorous processes employed to ensure the highest possible accuracy and reliability. We aim for complete transparency, outlining each step from initial data sourcing to final estimate publication. This detailed approach underscores our commitment to providing authoritative data and fostering informed public discourse.
core Principles & Data Sources
Our estimates are built upon a foundation of combining administrative data with large-scale survey data. We leverage the best available information from the U.S. Census Bureau, specifically the American Community Survey (ACS) and, for earlier years, the Current Population Survey (CPS). However, directly identifying unauthorized immigrants through surveys is impossible. Therefore, a multi-stage estimation process is employed, relying on a “residual” method. This involves determining the total foreign-born population (through surveys) and subtracting the estimated lawful foreign-born population (derived from administrative records).
The Estimation & Status Assignment Process: A Step-by-Step Breakdown
- Establishing the Lawful Foreign-Born Population: We begin by compiling the most current and comprehensive estimates of the lawful foreign-born population. This is based on data from sources like the Department of Homeland Security, tracking lawful permanent residents (green card holders), temporary visa holders, and other legally admitted immigrants. These figures serve as the benchmark (“L” in the equation: Unauthorized = total Foreign-Born – Lawful Foreign-Born).
- Survey Data Integration (ACS/CPS): We utilize data from the ACS (primarily) and CPS to determine the total foreign-born population (“S”). These surveys provide detailed demographic and socioeconomic information.
- Legal Status assignment: The core of our methodology lies in assigning a legal status to each immigrant within the ACS or CPS dataset. This is a complex process, utilizing a sophisticated algorithm that considers factors such as country of birth, year of entry, age, education, and reported socioeconomic characteristics. This assignment isn’t perfect, acknowledging inherent uncertainties, but it’s the most robust method available.
- Weight Adjustment for Representativeness: Crucially, the survey weights are adjusted to account for known undercounts in the foreign-born population, particularly as identified in the 2020 Census quality assessment (https://www.pewresearch.org/short-reads/2022/06/08/key-facts-about-the-quality-of-the-2020-census/). This ensures our estimates align with the best available demographic benchmarks for lawful immigrants and unauthorized migrants.Adjustments are made specifically for children and working-age adults within each relevant category.
- Dataset Refinement & Alignment: The resulting dataset – with assigned legal statuses and adjusted weights – is then further refined to align with state-level trends and ensure consistency across regions. This final adjustment ensures the dataset accurately reflects the overall immigration landscape.
State-Level Estimates: Balancing Microdata with Macro Trends
Estimating the unauthorized immigrant population at the state level requires a nuanced approach.
initial estimates: For states beyond the six largest (California, Texas, Florida, New York, Illinois, and New Jersey), initial estimates are derived directly from the tabulated totals of individuals assigned as unauthorized immigrants within the ACS/CPS data.
Trend Analysis & Smoothing: Recognizing that initial estimates can fluctuate, we incorporate a trend analysis. We assume a degree of smoothness in state-level trends from year to year. This involves examining changes in surrounding years to identify and correct for possibly anomalous results.
Weight Adjustment for State Totals: The final step involves adjusting the individual weights within each state to reconcile the initial estimates with the trend analysis. Larger adjustments are applied to states where the trend analysis reveals notable discrepancies. Throughout this process, we maintain consistency with national and regional totals.
Understanding the Margin of Error
It’s vital to understand the limitations inherent in any estimation process. Our estimates of the unauthorized immigrant population are calculated as the difference between a precise administrative estimate of the lawful foreign-born population and a survey-based estimate of the total foreign-born population. Therefore, the margin of error reflects the uncertainty associated with the survey-based estimate (the “S” in our equation).
Variance Calculation: For ACS
