Validity and reliability on three European language versions of the Safety Organizing Scale

The Safety Organizing Scale (SOS) offers a reliable snapshot of nurses' engagement in unit-level safety behaviors in hospitals. As no comparable questionnaire exists in German, French and Italian, we explored the psychometric properties of SOS translations into each of those languages.

The psychometric properties of the nine-item SOS were tested according to American Educational Research Association guidelines.

Between October 2009 and June 2010, 1633 registered medical and/or surgical nurses in 35 Swiss hospitals completed translated SOS questionnaires.

For each translation, psychometric evaluation revealed evidence based on content (scale-content validity index >0.89), response patterns (e.g. average of missing values across all items = 0.80%), internal structure (e.g. comparative fit indices >0.90, root mean square error of approximation <0.08) and reliability (Cronbach's alpha >0.79). We differentiated the scale regarding one related concept (implicit rationing of nursing care). Higher SOS scores correlated with supportive leadership and lower nurse-reported medication errors, but not with nurse-reported patient falls.

The SOS offers a valuable measurement of engagement in safety practices that might influence patient outcomes. Initial evidence regarding the validity and reliability of the translated versions supports their use in German, French and Italian. Concurrent validity will require confirmation via further analysis using more reliable outcome measures (e.g. mortality rates). The translated versions' predictive validity needs to be established in prospective studies.