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42 lines
2.1 KiB
42 lines
2.1 KiB
---
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module: analysis
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problem_type: best_practice
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date: 2026-05-25
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tags:
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- svd
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- overton-window
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- voting-patterns
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- policy-content
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- spatial-analysis
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category: best-practices
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---
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# SVD Positions Reflect Voting Patterns, Not Policy Content
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## Context
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When analyzing political shifts with SVD/PCA party positions, it is tempting to interpret spatial movement as ideological change — "centrists moved left" sounds like centrist parties became more progressive. This interpretation is incorrect and dangerously misleading.
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## Guidance
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**SVD axes capture agreement structure, not policy positions.** A party's coordinate on an SVD axis reflects whom it votes with and against, not what policies it advocates. This was already documented in `svd-labels-voting-patterns-not-semantics.md` for axis labeling, but the same principle applies to spatial drift analysis.
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**What SVD movement actually means:**
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- Centrists moving left on an axis means centrist voting patterns became *more distinct* from right-wing voting patterns
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- It does NOT mean centrist parties adopted more left-wing policy positions
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- It does NOT mean the motions being voted on became more left-wing or right-wing in content
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**Why this matters for Overton window analysis:**
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- "Acceptance without conversion" (centrists vote more with right-wing while spatially diverging) is a claim about *voting behavior*, not stated ideology
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- A right-wing motion can have high centrist support while still being in a "right-wing" cluster if centrist parties split on it
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- Topics with cross-partisan agreement (defense, nuclear energy) show minimal spatial separation regardless of how radical the motion text is
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## When to Apply
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- Before interpreting any SVD/PCA spatial drift as "ideological shift"
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- When presenting SVD movement findings to non-technical audiences
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- When cross-referencing voting-pattern results with content-based analysis (LLM extremity scores, mechanism classification)
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## Prevention
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Always pair SVD drift findings with a caveat: "SVD positions reflect voting patterns, not policy content. We measure behavioral shifts in voting coalitions, not ideological repositioning of party platforms."
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