The Safety Score is Tacit's own number from your real data: harsh events from Motive or Geotab, roadside inspections, DVIR defects and HOS violations, weighted and recomputed weekly. The CSA page explains the seven BASICs and shows the public percentiles for your DOT number. They differ on purpose: CSA is what FMCSA sees; the Safety Score is what you can change this week.