---
module: analysis/right_wing
problem_type: best-practice
date: 2026-05-25
tags:
  - overton-window
  - domain-decomposition
  - mp-level-analysis
  - party-disaggregation
  - migration-policy
  - centrist-voting
category: best-practices
---

# Domain Decomposition Reveals Hidden Variance in Overton Window Analysis

## Context

Aggregate centrist support for right-wing motions surged post-2024 (d=+0.65). But the aggregate masked two distinct stories: one of strategic moderation (85% of motions, non-migration domains) and one of genuine acceptance expansion (15%, migration domain). Without domain decomposition, the analysis would incorrectly claim either "no shift" or "complete shift" when both processes occurred simultaneously.

## Guidance

**Always decompose political shift analyses by policy domain before drawing conclusions.** The aggregate number answers a different question than each domain-specific signal.

**What to check per domain:**

1. **Volume change:** Did motion count increase or decrease?
2. **Material impact change:** Did the policy substance intensify or moderate?
3. **Centrist support change:** Did centrist parties accept more of these motions?
4. **MP-level disaggregation:** Which specific centrist parties drive the shift?

**The migration exception (2024 Dutch parliament):**
- Material impact barely changed (3.26→3.13)
- Yet centrist support more than doubled (0.153→0.369)
- M=5 support went from 0.000 to 0.185
- This is the one domain where acceptance genuinely expanded

**All other domains (climate, nitrogen, economy, defense, etc.):**
- Material impact significantly declined (2.72→2.30)
- High-impact share collapsed (20.8%→8.0%)
- M=5 motions: pre-2024 "exit Paris accord" (CS=0.0), post-2024 "build nuclear plants" (CS=1.0)
- Strategic moderation explains the shift

**Party-level disaggregation:**
- CDA and ChristenUnie (Christian-conservative centrists) more than doubled migration vote share
- D66 (secular-progressive) barely moved from single digits
- The shift is not "centrists" generally — it's a specific faction within the center

## Why This Matters

Without domain decomposition, an analyst would report "centrist support for right-wing motions increased" and either: (a) claim the Overton window shifted right (wrong — 85% of motions show content moderation, not acceptance expansion), or (b) claim the Overton window didn't shift (wrong — migration is the 15% where it demonstrably did). Domain decomposition prevents both errors and reveals the more honest picture: strategic moderation was the dominant mechanism, with migration as the sole measurable exception.

## When to Apply

- Before drawing conclusions from aggregate voting trend data
- When policy domains have different baseline extremity levels (migration already had M=5 motions; climate gained them post-Ukraine energy crisis)
- When centrist parties are ideologically heterogeneous (Christian-democrats ≠ progressive-liberals)
- When the target audience is academic or policy-oriented and will spot domain conflation

## Examples

**Bad:** "Centrist support for right-wing motions surged from 0.25 to 0.51 — the Overton window shifted."

**Good:** "Centrist support for right-wing motions surged from 0.25 to 0.51. Domain decomposition reveals two mechanisms: strategic moderation across 85% of motions (content became milder, centrists rewarded moderation), and genuine acceptance expansion in the migration domain (content impact stable, centrist support doubled)."
