Safety Organizing Scale (SOS)

National Center for Interprofessional Practice and Education's picture
Submitted by National Center... on Sep 6, 2016 - 11:12am CDT

Vogus, T. J.
Sutcliffe, K. M.

The tool was designed to capture self-reported team behaviors that underlie a safety culture within hospital-based nursing units. Specifically, this 9-item tool measures individual nurses' perceptions of how their nursing unit works in terms of: (1) preoccupation with failure, (2) reluctance to simplify interpretations, (3) sensitivity to operations, (4) commitment to resilience, and (5) deference to expertise.  Results, aggregated to the unit level, can be used to potentially improve patient safety through the evaluation of teamwork skills.  A validity study of 1,685 nurses (BSN, and other nursing credentialed staff) in 15 Catholic hospitals revealed a good factor structure and internal reliability. SOS scores at the unit level were also significantly related to reported medication errors and reported patient falls.

Link to Resources
Descriptive Elements
Who is Being Assessed or Evaluated?: 
Informal groups, networks, colleagues
Instrument Type: 
Self-report (e.g., survey, questionnaire, self-rating)
Source of Data: 
Health care providers, staff
Notes for Data Sources: 

1,685 registered nurses from 125 nursing units in 13 Catholic hospitals in the U.S., varying in hospital type and size.

Instrument Content: 
Behaviors / skills
Organizational environment, culture
Notes for Content: 

The SOS tool measuring nursing behaviors is a unidimensional measure of safety-related behaviors in hospital settings.  

Preoccupation with Failure

  • "When giving report to an oncoming nurse, we usually discuss what to look out for" 
  • "We spend time identifying activities we do not want to go wrong"

Reluctance to Simplify Interpretations

  • "We discuss alternatives as to how to go about our normal work activities"

Sensitivity to Operations

  • "We have a good 'map' of each other’s talents and skills
  • "We discuss our unique skills with each other so we know who on the unit has relevant specialized skills and knowledge"

Commitment to Resilience

  • "We talk about mistakes and ways to learn from them"
  • "When errors happen, we discuss how we could have prevented them"

Deference to Expertise

  • "When attempting to resolve a problem, we take advantage of the unique skills of our colleagues"
  • "When a patient crisis occurs, we rapidly pool our collective expertise to attempt to resolve it"

A related survey completed by respondents in the validation study addressed aspects of respondents' personal commitment and belonging (3 items), and trust in manager (2 items).

Instrument Length: 

9 items; time requirements are not specified. 

Item Format: 
9 item 7-point scale ranging from not at all (1) to a very great extent (7).
Paper-and-pencil instrument was mailed to respondents.
Scores are meant to be aggregated to the unit level.
None described.
Open access (available on this website)
Notes on Access: 

Can be partially viewed in journal article.  Contact author to confirm access.

Psychometric Elements: Evidence of Validity
Items were developed based on the safe performance literature around high-reliability organizations (HROs). Specifically, 5 processes were targeted: preoccupation with failure, reluctance to simplify interpretations, sensitivity to operations, commitment to resilience, and deference to expertise. Items were linked to nursing through review of case studies. A review panel (i.e., 7 experts in HROs and nursing) assessed the content validity of the measure. Finally, 45 coronary care unit nurses pretested the SOS.
Response Process: 
Response rate was moderate (i.e., 1,685 of 3,298 or 51.1%).
Internal Structure: 
Confirmatory factor analysis demonstrated good fit, Comparitive Fit Index (CFI) = 0.96, Incremental Fit Index (IFI) = 0.96, Root Mean Square Error of Approximation (RMSEA) = 0.06, Standardized Root Mean Square Residual (SRMSR) = 0.03. Internal consistency reliability (i.e., Cronbach’s alpha) for the SOS was 0.88. At the unit level, the ICC(2) value for the SOS acceptable at 0.74.
Relation to Other Variables: 
The tool is linked to increased patient safety. The SOS is negatively related to reported medication errors (beta = -0.68, p < 0.001) and reported patient falls (beta = -0.63, p < 0.001).
None described.