Peer-Reviewed Research
The Beach Safety Hierarchy Assessment Scale
Development, Factor Structure, and Preliminary Validation of a Five-Level Model of Nervous System Readiness in Trauma-Affected Intimate Relationships
The Beach Safety Hierarchy Assessment Scale (BSHAS) is a validated psychological instrument developed by Scott Beach, RPh, LCDC-II. It quantifies and measures what the book Lead with Safety describes experientially: that safety in a trauma-affected intimate relationship is not a single state, but a five-level hierarchy, and that the nervous system must move through these levels in sequence before higher-order relational functioning becomes possible.
What the Research Found
A Clear Hierarchy Exists
The data confirmed that the five levels do form a genuine hierarchy — not just a collection of unrelated constructs. Nervous system safety (Level 1) must be present before emotional safety (Level 2) becomes accessible. Emotional safety must be stable before relational connection (Level 3) can form. And so on up the hierarchy.
The L3–L4 Gap
One of the most significant findings was what the research calls the “L3–L4 gap.” The transition from relational safety (Level 3) to cognitive processing (Level 4) is significantly larger than any other transition in the hierarchy. This means that relational connection — feeling safe with a person — does not automatically enable cognitive engagement. There is a distinct additional threshold that must be crossed.
This explains why many couples can feel warm and connected and still fail at conversations. Warmth is Level 3. Cognitive engagement requires Level 4, and the gap between them is real and measurable.
Dyadic Concordance
Partners tend to see the system as operating at a higher level than the person with DID experiences internally. Partners observe behavior; they don’t feel the internal state. This systematic discrepancy — partners overestimating the level — helps explain one of the most common mismatches in these relationships: the partner who believes the conversation is possible, and the person with DID who is not actually available for it yet.
Directional Observer Bias
The research also identified a directional bias: partners are more likely to overestimate the level than to underestimate it. This has direct clinical implications — it means partners should consistently assume the level is lower than it appears, not higher.
The Five Levels (Summary)
Nervous System Safety
Physiological regulation sufficient to remain present without entering defense mode.
Emotional Safety
The emotional environment is non-threatening; feelings can be expressed without fear of punishment or dismissal.
Relational Safety
Connection without defense; the partner’s presence is experienced as safe rather than threatening.
Cognitive Processing
The capacity for information processing, planning, and substantive conversation.
Insight and Growth
Reflective capacity; the ability to recognize and understand one’s own patterns.
The full academic paper — including methodology, data, factor analysis, and discussion — is available at the dedicated research site.