Data Processing

Crosstabs is built around a local-first analysis flow. This page documents what is processed locally and what can leave the browser.

Local workflow

  • Uploaded files are parsed in the browser into rows and variable metadata.
  • Crosstab computation, filters, weighting, recodes, statistics, charts, and exports are produced from browser state.
  • Saved projects and saved analysis templates use browser localStorage on the same device and browser profile.

AI workflow

  • Browser-local Gemma uses the configured model URL after explicit user confirmation and a WebGPU-capable browser.
  • Server AI is opt-in from the AI panel and receives a structured crosstab summary, not the original spreadsheet file.
  • The server AI path should be disabled or replaced before analyzing regulated data that cannot be sent to the configured provider.

Exports and retention

  • PDF and XLSX reports include audit metadata such as source file name, filters, weight variable, missing-value setting, report title, analyst, and generated timestamp.
  • CSV exports sanitize spreadsheet formula prefixes to reduce spreadsheet-injection risk.
  • Crosstabs does not currently provide account-level retention controls because the public app has no account system.