Vertical Development InstituteEnquire

Group Deliberation Inventory GDI®Building capacity for collective wisdom.

The GDI® measures how your team reasons together through problems no one can solve alone - the groundwork of wise collective action.

Bring the GDI® to your teamExplore the science

Build your team’s developmental repertoire across seven lines and six stages of meaning-making.

Click on any key or stage label to explore the tool.

Why it exists

The hardest challenges organisations face are no longer technical, but adaptive. No individual - however capable - can solve them alone. They are complex, ambiguous and require intentionally activating collective intelligence.

The GDI® helps teams develop their capacity to deliberate together and harness the wisdom of the group through conscious conversations.

01 — The instrument

A psychometric for the conversation itself

Most team assessments capture what a group does or what it produces. The GDI® measures the developmental complexity of how the team reasons and decides together through complex problems - the collective meaning-making structure underneath the behaviour.

Researchers call this emergent property of a group “collective deliberation”. It is the shared reasoning about a question on which thoughtful people can reasonably disagree. Strategic decisions, organisational dilemmas, responses to disruption: how a team thinks and works through these is a capacity in its own right, distinct from the individual capacities of its members. A group of individually brilliant thinkers can reason poorly together. A group with a mix of profiles can produce thinking none of its members could have produced alone. The difference lies in the quality of the interaction, and the interaction is what the GDI® measures.

Deliberation is not discussion - discussion can wander without a question to resolve. Nor is it debate, which is something to be won rather than resolved. And it is not consensus-seeking: a group can deliberate well and still disagree. It is shared reasoning toward a co-created position that the group can stand behind.

02 — What it measures

Seven lines of development. Six stages. One profile.

Within a single deliberation, a group’s reasoning about the problem can be more sophisticated than its handling of disagreement. Its time horizons can outrun its attention to its own process. The GDI® scores seven distinct lines, distinct aspects of a group’s deliberation, each against six stage-qualities of developmental complexity.

What a profile looks like

Opportunist
Diplomat
Expert
Achiever
Redefining
Transforming
  • ATTNAttention
  • TIMETime
  • POWERPower
  • COLLCollaboration
  • PERSPPerspective-Taking
  • FDBKFeedback
  • SYS THINKSystemic Thinking
gold ring = strengthslate ring = growth edgeglowing octave = centre of gravity

What the commentary sounds like

Developmental AI™ team report

Sample excerpt

Systemic thinking

Aligned
You rated · RedefiningThe conversation showed · Redefining

You rated your systemic thinking at Redefining, and the conversation showed the same quality. The group kept tracing how one move would ripple through the wider system, and twice paused its own momentum to test whether it was solving a symptom or the real problem. What might it take for that mindful pause to become a habit for your team?

“I wonder if we are on the right track with this train of thought, or if this is just an aspect of a bigger issue. What’s connecting all these dots?” · 14:32

Feedback

Growth edge
You rated · AchieverThe conversation showed · Diplomat

Your group saw its feedback practice at Achiever; the transcript suggests the conversation operated closer to Diplomat. Disagreements tended to be smoothed before they could inform the decision - a hesitant objection was met with quick reassurance rather than curiosity. We wonder what might open up if the group stayed with one uncomfortable observation a little longer.

“Maybe, but - no, it’s probably fine, let’s keep moving.” · 27:08

Illustrative sample. In a real report, every observation is anchored to your team’s actual words - quoted and time-stamped from the conversation.

A GDI® profile is not a verdict on a team’s performance, nor a label for any of its members. It describes one deliberation at a particular moment in time. The same group can deliberate differently at a different time. This is the power of the GDI®: illuminating the features of deliberation as a collective capacity that can be developed.

03 — How it works

One conversation, three vantage points

  1. The challenge

    Your team engages in a real-world conversation or a specially designed simulation - either way, the deliberation has to focus on problems that resist simple solutions: unfamiliar, irreducibly complex, time-pressured, with no right answer in sight. Under that heat, a group’s real patterns surface. The GDI® is administered and debriefed by a certified facilitator.

  2. The questionnaire

    Immediately after the conversation, every member rates the quality of the group’s deliberation across 77 observable behaviours. This forms the spine of the GDI® - the group’s own perception of what just happened.

  3. The analysis

    A research-based Developmental AI™ analyses the full transcript of the conversation and independently scores the same interaction across seven lines and six stages - utterance by utterance, exchange by exchange, across the whole arc of the deliberation. A detailed, customised report is generated on the spot, detailing each stage and line as it emerged in the interaction and supported by quotes from the team’s conversation.

  4. The observation

    A developmentally trained facilitator captures a third perspective on the group’s dynamic: non-verbal cues, power flows, pacing, and interaction patterns that go beyond the words being said.

  5. The debrief

    The group receives a report placing their own GDI® perspective side by side with the Developmental AI™ analysis, and both are informed by the facilitator’s mirroring. The group engages in an immersive exploration of its patterns, exploring strengths, edges, hidden dynamics and crafting its own collective growth experiment. The ultimate intention is to support teams in creating practical ways to stretch and train their collective capacity for operating in complexity.

04 — The science

A new instrument and five decades of foundational research

The Group Deliberation Inventory GDI® is a pioneering instrument sitting at the intersection of several fields of research and practice: adult (vertical) development (bridging three different traditions - ego development, constructive developmental theory and hierarchical complexity), group dynamics, team coaching, adaptive leadership and organisational development. The GDI® questionnaire is the first ever to measure the developmental properties of deliberation as a team emergent state.

A formal paper exploring the construct and the structure of this tool is currently in its final stages of revision. The questionnaire is in its third stage of validation, after having passed two rounds of expert validation of its items by experts in developmental theory. The full instrument (questionnaire and Developmental AI™ assessment) and debrief protocol are now in the group validation stage - testing factor structure, convergent and discriminant validity - with more than 100 groups due to undertake it before the final version is publicly released.

The GDI® builds on decades of research on how adult meaning-making grows towards more maturity and takes it to the next level, exploring how groups and collectives can grow in the ways they make sense of complexity together.

Our highest aspiration is for this tool to become a companion to teams and organisations as they strive to grow their collective capacity to tackle some of the most burning challenges humanity is facing today. We believe none of our biggest problems can be solved alone, but we trust we can find ways forward together if we get better at truly harnessing the potential of our collective intelligence through wise conversations and thoughtful decision-making. Our hope is that GDI® will become a mirror and a tool to accelerate our capacity for accessing collective wisdom.

For more details about the science informing this tool, explore our VDI research page.

Ready to see how your team thinks and decides together?

The GDI® runs as a facilitated team experience - on its own, or inside a leadership development program.

Start a conversation