EV-0034
Whether people will speak is a property of the group, and it is measurable
Frazier, M. L., Fainshmidt, S., Klinger, R. L., Pezeshkan, A., & Vracheva, V. (2017). Personnel Psychology, 70(1), 113-165 · Source
What this entitles us to say
A meta-analysis of 136 independent samples covering over 22,000 individuals and roughly 5,000 groups, establishing psychological safety as a measurable group property with identifiable antecedents - leadership and work design chief among them - and relationships to learning, performance and engagement.
What it found
136 independent samples, over 22,000 individuals and roughly 5,000 groups. The analysis mapped the antecedents and outcomes of psychological safety and compared effect sizes to establish which antecedents matter most. Leadership and work design emerged among the strongest antecedents, and psychological safety related to learning behavior, performance and engagement.
Why it matters here
It is the bridge between two traits and it belongs to both. For Respect, it is the measurable consequence of how a leader treats people - the accumulated result of many small exchanges of the kind EV-0033 studies one at a time. For Courage, it is the condition under which speaking up is possible at all: EV-0039 shows what voice costs a person, and this is the variable that decides how high that cost is.
The finding that leadership is among the strongest antecedents is the one that matters commercially. It places the variable inside the leader's control, which is the only place a leadership program can legitimately act.
One thing to hold onto against the fashion: psychological safety is not comfort and it is not agreement. The original research found safer teams reporting more errors, not making fewer. The module should teach it as the freedom to say the difficult thing, never as the absence of difficulty.
The limits
Mostly correlational and self-reported. The construct has become fashionable, which brings the usual problem of a term being stretched until it means "a nice team" - it does not mean that, and the module must not let it drift. It is also predominantly studied in knowledge work; the transfer to a production floor or a job site is plausible but less evidenced. Verified to abstract level.
What we do not say
"Psychological safety means a comfortable team." It means people can raise problems without being punished, which frequently makes a team less comfortable, not more.