The relationship between staffing and adverse events in Washington State hospitals: a cross-sectional study using linked hospital data.

Objective: To quantify the relationship between staffing characteristics and patient outcomes in acute care hospitals in Washington state.

Methods: Retrospective cross-sectional time-series study of linked data from six sources on staffing and outcomes for Washington state hospitals. Key stakeholders provided input on data sources, measures, and outcomes in a four-phase participatory process.