Domain 2, Systems Thinking, Human Factors Engineering, and Design, is 20% of the scored CPPS exam. The content outline names only a few frameworks explicitly: SEIPS, Safety-I and Safety-II, and high reliability. That makes them some of the most predictable content on the test.
Why systems thinking
Healthcare is a complex system: many parts, many people, constant change. Harm rarely has a single cause. James Reason's "Swiss cheese" model captures this: each layer of defense has holes, and harm happens when the holes line up. The systems approach asks how the layers failed, not who failed.
SEIPS
The Systems Engineering Initiative for Patient Safety (SEIPS) model, developed by Pascale Carayon and colleagues, links three parts:
| Part | What it includes |
|---|---|
| Work system | The person, tasks, tools and technology, organization, and physical environment. Later versions add the external environment, such as regulations and policy. |
| Processes | Care and work processes: the work done by clinicians, patients, and both together. |
| Outcomes | Patient outcomes, employee outcomes, and organizational outcomes. |
Two points matter for the exam. First, the person sits at the center of the work system, and the other elements interact with them. Second, outcomes include employee well-being, which fits the outline's treatment of workforce safety as core content. Feedback loops mean outcomes reshape the work system over time.
On a question, SEIPS helps you spot contributing factors beyond the individual: a confusing interface (tools), a poor handoff structure (organization), a noisy medication room (environment).
Safety-I and Safety-II
| Safety-I | Safety-II | |
|---|---|---|
| Definition of safety | As few things as possible go wrong | As many things as possible go right |
| What you study | Failures and adverse events | Everyday work, including how things usually succeed |
| View of people | A source of variability to control | A source of flexibility and resilience |
| Typical tools | RCA, incident reports | Studying work-as-done, learning from success, resilience engineering |
Safety-II, associated with Erik Hollnagel, doesn't replace Safety-I. The two complement each other. A key Safety-II idea is the gap between work-as-imagined (policies and procedures) and work-as-done (what people actually do to get the job done). Closing that gap by understanding real work is often more useful than writing another rule.
Domain 2 questions test application, not definitions. Try them free.
Try 50 free questionsHigh reliability
High reliability organizations operate in hazardous environments, like aviation and nuclear power, yet have far fewer accidents than expected. Karl Weick and Kathleen Sutcliffe described five principles:
- Preoccupation with failure: treat small errors and near misses as warning signs.
- Reluctance to simplify: resist easy explanations and dig into complexity.
- Sensitivity to operations: stay aware of what's happening on the front line right now.
- Commitment to resilience: expect failures and build the ability to detect, contain and recover.
- Deference to expertise: in a crisis, decisions go to the people with the most relevant knowledge, not the most senior title.
The first three are about anticipating problems; the last two are about containing them. Safety huddles, leadership rounding and escalation without fear are common healthcare practices built on these ideas.
Human factors essentials
- Cognitive bias: anchoring, availability bias, confirmation bias and premature closure all contribute to diagnostic error.
- Human limits: fatigue, interruptions, workload and memory capacity make errors predictable. Design around them rather than asking people to try harder.
- Usability: test devices and software with real users doing real tasks before rollout. Heuristic evaluation and simulation are common methods.
- Design for safety: forcing functions, standardization, and making the right action the easy action.
- Cost and benefit: the outline includes resources and cost when selecting a design solution.
Practice questions
Practice question 1
During a code, a respiratory therapist notices the ventilator settings are wrong and speaks up. The attending physician immediately defers to the therapist's recommendation. Which high reliability principle does this show?
- Reluctance to simplify
- Sensitivity to operations
- Deference to expertise
- Preoccupation with failure
Show answer
Answer: C. Decision-making moved to the person with the most relevant expertise, regardless of hierarchy.
Practice question 2
A safety team wants to understand why the new discharge process usually works well despite frequent staffing gaps. Which approach does this reflect?
- Safety-I
- Safety-II
- Failure mode and effects analysis
- Just culture
Show answer
Answer: B. Studying how everyday work succeeds, and the adaptations people make, is the core of Safety-II.
Practice question 3
Using the SEIPS model, a nurse's medication error is linked to an infusion pump interface that requires nine screens to program a dose. Which work system element is involved?
- Person
- Organization
- Tools and technology
- Physical environment
Show answer
Answer: C. The pump interface is a tool and technology issue. Redesigning it is a stronger fix than retraining the nurse.
Frequently asked questions
Systems Engineering Initiative for Patient Safety. The model links the work system (person, tasks, tools and technology, organization, environment) to processes and to patient, employee and organizational outcomes.
Safety-I defines safety as few things going wrong and learns mainly from failures. Safety-II defines it as many things going right and learns from everyday successful work.
Preoccupation with failure, reluctance to simplify, sensitivity to operations, commitment to resilience, and deference to expertise.
Work-as-imagined is how policies say work should happen; work-as-done is how people actually do it. Understanding the gap is a key Safety-II idea.
Sources
- CBPPS, CPPS Examination Content Outline (published September 2024), linked from IHI’s CPPS examination page.
- Carayon P, et al. Work system design for patient safety: the SEIPS model. Quality & Safety in Health Care (2006).
- Hollnagel E. Safety-I and Safety-II (2014).
- Weick KE, Sutcliffe KM. Managing the Unexpected.
- Reason J. Human error: models and management. BMJ (2000).
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