2.7 KiB

Raw Blame History

session	updated
ses_2b4f	2026-04-01T21:57:48.280Z

Session Summary

Goal

Analyze how the SVD Components tab in explorer.py computes party positions, focusing on: data loading flow, window_size default, X/Y coordinate computation, and whether positions are individual MPs or party centroids.

Constraints & Preferences

Provide exact file:line references for all code paths
Trace data flow through multiple files and functions
Answer 4 specific questions about the SVD Components tab implementation

Progress

Done

Analyzed build_svd_components_tab() at explorer.py:2449-2867
Traced load_positions() at explorer.py:603-656 — default window_size is "quarterly"
Traced load_party_axis_scores() at explorer.py:836-853
Traced _load_mp_vectors_by_party() at explorer.py:778-832
Analyzed compute_2d_axes() at analysis/political_axis.py:131-476
Analyzed compute_party_bootstrap_cis() at analysis/political_axis.py:624-695
Analyzed compute_party_centroids() at explorer_helpers.py:246-317
Documented complete data flow with file:line references

In Progress

(none — analysis complete)

Blocked

(none)

Key Decisions

Window size: The SVD Components tab uses "quarterly" as the default window_size (via load_positions() at line 604)
Position type for components 1-2: Party centroids computed as mean(x), mean(y) from individual MP PCA projections (line 2747)
Position type for components 3-10: Mean SVD vector per party, with component value extracted by index
Data source: svd_vectors table filtered by entity_type='mp' and window_id='current_parliament'

Next Steps

(No pending work — analysis was completed)

Critical Context

For components 1 and 2: Party positions come from load_positions() which performs PCA on Procrustes-aligned MP SVD vectors, then computes party centroids by averaging x/y coordinates of all MPs in that party
For components 3-10: Party positions come from load_party_axis_scores() which computes mean SVD vector per party from window='current_parliament'
Bootstrap CIs: Computed via _cached_bootstrap_cis() at explorer.py:873-880 using compute_party_bootstrap_cis() from analysis/political_axis.py
MP→Party mapping: Via mp_metadata table, normalized using _PARTY_NORMALIZE dict at explorer.py:471-480

File Operations

Read

/home/sgeboers/Projects/stemwijzer/explorer.py (full file: lines 1-3094)
/home/sgeboers/Projects/stemwijzer/analysis/political_axis.py (full file: lines 1-695)
/home/sgeboers/Projects/stemwijzer/explorer_helpers.py (full file: lines 1-317)

Modified

(none)

2.7 KiB Raw Blame History