# SPA bargain research pack

This pack contains a research-grade article draft, source-derived data, model-derived amortization grids, and a benchmark registry template.

Files:
- `article_spa_bargain.md`: full manuscript with Harvard-style references.
- `rum_source_observations.csv`: exact source-derived RUM ratios from Russell's published RUM Archive charts.
- `break_even_summary.csv`: compact break-even table for common first-load penalties.
- `amortization_grid.csv`: full sensitivity grid for initial SPA penalty and soft-navigation saving assumptions.
- `matched_journey_registry_template.csv`: 50-pair / 5-step pre-registration template for the proposed lab fleet. It is intentionally blank for URLs; filling it after seeing measurements would create selection bias.
- `required_saving_curve.png`: required soft-navigation saving at observed RUM ratios.
- `break_even_depth_curve.png`: total session depth required to amortize for common saving assumptions.
- `sources.json`: source URLs used in the pack.

Data provenance:
The data are source-derived and model-derived, not fabricated lab measurements. The RUM ratios are calculated from the published chart percentages in Russell (2025): desktop 27.2/27.6 and mobile 23.1/26.4. The amortization grids are deterministic transformations of the equation P <= r*delta.