# Majority Minority Change

> This skill should be used when users need to analyze county-level racial composition change between two Census snapshots and identify where places crossed a majority-minority threshold.

- Skill: `amkessler/majority-minority-change` (Agent Skill, multi-file: 6 files)
- Install (CLI): `npx skillmds@latest add amkessler/majority-minority-change`
- Raw SKILL.md: https://api.skillmd.com/api/skills/amkessler/majority-minority-change/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: amkessler (https://skillmd.com/u/amkessler)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/amkessler/majority-minority-change

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# Majority Minority Change

Use this skill to compare county demographics across two years and flag threshold crossings.

## Requirements

- R with `dplyr`, `readr`, `stringr`, and `jsonlite`
- Two local CSV files with county identifiers and required race/population fields
- Bundled Census CSV snapshots for immediate use:
  - `skills/majority-minority-change/data/county_race_acs5_2010.csv`
  - `skills/majority-minority-change/data/county_race_acs5_2020.csv`
- No API key required

## Required Input Columns

- Join keys available in both files:
  - `county_fips` (preferred), or
  - both `state` and `county`
- Metrics in both files:
  - `total_population`
  - `non_hispanic_white`

## Standard Workflow

1. Confirm start/end files and year labels.
   - `--state` accepts full names or USPS abbreviations (for example, `Georgia` or `GA`).
   - Default bundled files:
     - start: `skills/majority-minority-change/data/county_race_acs5_2010.csv`
     - end: `skills/majority-minority-change/data/county_race_acs5_2020.csv`
2. Review `skills/majority-minority-change/references/DATA_SCHEMA.md` for exact derived/output field names before downstream filtering or selecting columns.
   - Expected output naming includes `nonwhite_share_<year_label>` and `delta_nonwhite_share_pp`.
3. Run script with optional state filter.
   - Example:
     `Rscript skills/majority-minority-change/scripts/analyze_majority_minority_change.R --input-start skills/majority-minority-change/data/county_race_acs5_2010.csv --input-end skills/majority-minority-change/data/county_race_acs5_2020.csv --start-label 2010 --end-label 2020`
4. Review counties with largest percentage-point shifts and threshold crossings.

## Output

Return:
- non-white share in each year
- percentage-point change
- `crossed_to_majority_minority`
- `crossed_out_of_majority_minority`