Only 6 of 168 Intervention Studies Measured Psychological Safety as a Team Outcome
Psychological safety is a property of a team. A survey that asks individuals how they feel and averages the answers, without checking that the team's members actually agree, produces a number that cannot support the decision it is bought to support.
Built from Her own unpublished review of 667 intervention studies across five systematic research matrices: 168 were carried through to extraction, and 6 of those measured psychological safety as an outcome with team-level checks. Because the review is unpublished, a reader cannot check its counts against a published source. Alongside it: Edmondson (1999), which defined team psychological safety and tested it in 51 teams; Li and Tang (2022), a recent study that reports the full set of checks; Grailey et al. (2021) on how varied the methods are in healthcare research; and Google's Project Aristotle guide (2015). References at the foot.
Does not establish That the instruments are useless, or that individual-level data is worthless. It establishes a narrower and harder thing: that an average of individual answers cannot answer a question about a team until the team's members are shown to agree, however many individuals you collect it from. That is a limit on the inference, not on the instrument.
Your organization probably measures psychological safety. Many do now—it’s become common practice since Google’s Project Aristotle ranked it first among the things that made its teams effective, a decade ago.
Here’s the problem: you’re likely measuring it wrong.
This isn’t a minor technical issue. It’s a fundamental category error that can render psychological safety data meaningless for the decisions organizations actually need to make.
After analyzing 667 intervention studies across organizational psychology, a striking pattern emerged. Of the 168 studies carried through to extraction, only 6—3.6%—measured psychological safety as an outcome, at the team level, with the checks that show a team actually shares the belief. The rest include studies that did not measure it at all.
Understanding why this matters requires going back to what psychological safety actually is, and why that definition creates measurement requirements organizations often ignore.
What Psychological Safety Actually Is
In 1999, Harvard researcher Amy Edmondson defined psychological safety as “a shared belief held by members of a team that the team is safe for interpersonal risk-taking.”
Three words in that definition create the measurement problem: “shared belief” and “team.”
Psychological safety isn’t an individual attitude. It’s not how safe you feel. It’s how safe we collectively perceive our team to be. This distinction sounds academic. It’s actually the whole ballgame.
When Edmondson studied 51 work teams, she didn’t just ask individuals whether they felt safe. She calculated whether team members’ perceptions converged—whether people on the same team gave similar answers, and whether those answers differed from other teams.
The statistical test for this is called an Intraclass Correlation Coefficient (ICC). Edmondson’s ICC was .39—meaning 39% of the variation in individual responses was attributable to team membership. People on the same team perceived similar levels of safety. People on different teams perceived different levels.
That met the test for treating psychological safety as a team-level variable. It existed at the team level, not just in individual heads.
.39 Edmondson’s ICC for team psychological safety across 51 teams — high enough to meet the test for treating it as a property of the team, not of the individual.
What Most Organizations Do Instead
Now consider what organizations commonly do when they “measure psychological safety.”
They administer a survey. Employees respond individually. Someone averages the responses—either across the whole organization or by department. Leadership receives a report: “Our psychological safety score is 3.8 out of 5.”
This approach commits a fundamental measurement error. It treats a team-level construct as an individual-level attitude. It’s like measuring “team coordination” by averaging individuals’ hand-eye coordination scores.
The problems cascade:
Problem 1: Averages Hide the Teams That Differ
An organization-wide average of 3.8 could mean universal mediocrity—or it could mask excellent teams hiding alongside toxic ones. Without team-level data, you can’t tell the difference.
Problem 2: No Validation That Teams Actually Share Perceptions
If team members disagree wildly about psychological safety—one person rates it 6, another rates it 2—averaging those scores produces a meaningless number. True psychological safety requires convergence. If people on the same team don’t share perceptions, you’re not measuring psychological safety. You’re measuring something else: perhaps individual personality differences, or personal relationships with managers.
Proper measurement calculates ICC to verify convergence. Without this step, you can’t know whether your data represents actual team-level psychological safety or just noise.
Problem 3: Improvements Get Diluted in Aggregate Data
Imagine you run an intervention. Three teams improve dramatically. Seven teams show no change. Your organization-wide average barely moves.
Leadership concludes: “The intervention didn’t work.”
Actually, the intervention worked brilliantly in three teams. You just can’t see it because you’re measuring at the wrong level. The information that would tell you what worked and why is invisible in aggregate data.
Problem 4: You Can’t Target Interventions Accurately
Without team-level measurement, you can’t identify which teams need attention. You can identify departments or locations with lower averages, but within those units, the actual problem teams remain hidden among higher-performing teams that pull up the average.
Resources get spread across entire departments when they should be concentrated on specific teams with specific issues.
The Research Evidence
This isn’t theoretical criticism. The measurement gap shows up clearly in research.
My analysis of 667 intervention studies across five research matrices found a striking pattern: psychological safety was frequently mentioned but rarely measured as an outcome at the team level.
When I examined how studies actually operationalized psychological safety:
Only 6 of the 168 studies carried through to extraction (3.6%) measured psychological safety as an outcome with team-level checks. The other 162 are not all failures—some never set out to measure psychological safety. What the count shows is how little of the intervention research can tell you whether a team’s psychological safety changed.
Why the gap? Four factors help explain it:
Statistical complexity. Proper team-level measurement requires ICC calculation, minimum team sizes, and validation that aggregation is justified. Only 6 of the 168 intervention studies I reviewed reported them for psychological safety as an outcome.
Time horizon mismatch. Psychological safety is a shared belief, built up over time. Organizations and researchers want faster results, so they measure outcomes that move more quickly.
Construct confusion. Many studies measure related but distinct constructs—psychosocial safety climate (organizational-level), positive workplace climate (broader), supportive supervision (antecedent), voice behavior (consequence). These proxies aren’t psychological safety as Edmondson defined it.
Healthcare measurement challenges. In healthcare, the sector’s conditions compound the problem: high turnover, rotating shifts, unstable team composition. A review of 62 studies of psychological safety in healthcare found “a wide range of methods” in use, and saw scope to harmonize them (Grailey et al., 2021).
“If team members don’t converge in their perceptions, averaging their responses produces a meaningless number. You’re not measuring psychological safety—you’re measuring statistical noise.”
What Proper Measurement Actually Looks Like
Measuring psychological safety correctly requires four elements organizational surveys often skip:
1. Team-Level Administration
Survey by team, not by department or organization. Define “team” consistently: people who work interdependently toward shared goals. The team is the unit of analysis—not the individual, not the department.
2. Sufficient Sample Within Teams
You need enough respondents in each team for their answers to be compared with each other. Edmondson had 86 percent of team members respond. With only 1-2 responses per team, you can’t distinguish signal from noise.
3. ICC Calculation and Validation
Before aggregating individual responses to team-level scores, calculate ICC to verify that team members’ perceptions actually converge.
.04 Edmondson’s ICC for job involvement, an individual attitude she measured alongside psychological safety. It did not differ significantly from team to team, so it could not be read as a property of the team.
ICC interpretation matters. Edmondson’s test was that team members’ answers had to agree with each other and differ from other teams’ enough to show up as a real difference between teams. Psychological safety came out at .39. Two individual attitudes in the same survey, internal motivation and job involvement, came out at .03 and .04 and did not differ significantly across teams. That is what a measure that does not belong to the team looks like.
A recent study shows the fuller set of checks. Li and Tang (2022) adapted Edmondson’s seven items and surveyed 356 employees in 90 teams. They reported within-team agreement (rwg = .96), the ICC (.38) and the reliability of the team average (ICC2 = .71) before treating psychological safety as a team score.
4. Validated Instrumentation
Use Edmondson’s 7-item scale or a properly validated adaptation. The items matter. Sample items include:
“If you make a mistake on this team, it is often held against you.” (reverse-scored)
“Members of this team are able to bring up problems and tough issues.”
“It is safe to take a risk on this team.”
Avoid creating ad-hoc items or using “psychological safety” questions from generic engagement surveys—they typically haven’t been validated at the team level.
What This Means Practically
If you’re measuring psychological safety (or planning to), here’s what to do differently:
Stop reporting organization-wide averages. They’re meaningless for psychological safety. Report team-level scores, and identify the distribution: how many teams fall in each range?
Calculate and report ICC. If you can’t demonstrate within-team convergence, you can’t claim to have measured psychological safety. You measured individual perceptions that happened to use psychological safety wording.
Use the data for team-level decisions. Which teams need intervention? What differentiates high-scoring teams from low-scoring ones? Are there patterns by manager, tenure, or other factors?
Track team-level change over time. After interventions, did specific teams improve? Did the intervention work better in some contexts than others? Organization-wide averages can hide this signal—team-level data reveals it.
Be honest about what you’re measuring. If you can’t implement team-level measurement (too few people per team, can’t ensure confidentiality within small teams), acknowledge that you’re measuring individual perceptions of safety—which is useful data, but isn’t psychological safety as the construct was defined and validated.
The Bottom Line
The gap isn’t about incompetence. It’s about convenience. Individual-level surveys are easier to administer, analyze, and explain. Team-level measurement requires more sophisticated design and analysis.
But easier isn’t the same as valid.
Psychological safety predicts team performance because it’s a team-level phenomenon—a shared perception that emerges from collective experience. Measuring it at the individual level and averaging up doesn’t capture the construct. It captures something else wearing the same name.
Organizations making decisions based on improperly measured psychological safety data are flying blind. They’re investing resources in interventions they can’t properly evaluate. They’re likely missing the team-level dynamics that actually drive performance.
Organizations that measure at the team level have a significant advantage: they can see what’s actually happening in their teams, target interventions precisely, and track whether those interventions work.
That’s not a marginal improvement. It’s the difference between actionable intelligence and expensive guessing.
References
Angelucci MV. Review of 667 intervention studies across five systematic research matrices; 168 studies carried through to extraction. Unpublished.
Edmondson A. Psychological safety and learning behavior in work teams. Administrative Science Quarterly. 1999;44(2):350-383. doi:10.2307/2666999
Google re:Work. Understand team effectiveness. Published 2015. Accessed October 13, 2026. https://rework.withgoogle.com/intl/en/guides/understand-team-effectiveness
Grailey KE, Murray E, Reader T, et al. The presence and potential impact of psychological safety in the healthcare setting: an evidence synthesis. BMC Health Services Research. 2021;21(1):773. doi:10.1186/s12913-021-06740-6
Li T, Tang N. Inclusive leadership and innovative performance: a multi-level mediation model of psychological safety. Frontiers in Psychology. 2022;13:934831. doi:10.3389/fpsyg.2022.934831
https://www.meaganangelucci.com/writing/why-psychological-safety-assessments-miss-the-pointPublished Dec 15, 2025