Most team tools help people describe how they behave. SDI, the Strength Deployment Inventory developed by Tim Overman and now published by Core Strengths, does something more specific: it helps people understand why they behave as they do, what motivates them at a deeper level, and crucially, what happens to their strengths when they feel threatened or when conflict enters the room. That third piece is where most of the useful work happens.
1. The real-world scenario
What SDI is based on
SDI is grounded in Relationship Awareness Theory, developed by Elias Porter in the 1970s. At its core, the theory holds that behaviour is driven by underlying motives: what we are fundamentally trying to achieve in our relationships and our work. Porter identified three core motivational value systems, a concern for people and relationships, a concern for results and task completion, and a concern for process and careful thinking, and argued that most people have a blend of these, with one or two more dominant.
2. What may be happening
What the SDI model shows
The SDI produces a profile that maps where a person sits across these motivational dimensions, both in conditions where things are going well and in conditions of conflict or pressure. This second dimension, what happens under pressure, is what distinguishes SDI from many other tools. It reveals not just how someone prefers to operate but how they are likely to behave when they feel challenged, misunderstood, or at risk. For leadership teams, this is often the most valuable data, because it is precisely in those moments that relationships and performance are most at risk.
3. Why it lands harder than expected
Overdone strengths: the most useful idea in the model
Every strength in the SDI model has an overdone version. The person who is driven by care for relationships may, under pressure, become so concerned with harmony that they avoid necessary conflict. The person driven by results may, under pressure, become so focused on the outcome that they override other people's concerns. The person driven by careful process may, under pressure, become so risk-averse that they slow down decisions that need to be made. These are not character flaws. They are strengths that have passed the point of usefulness. Naming them takes the personal charge out of the feedback conversation.
4. What actually helps
How it differs from MBTI or DISC
Where Myers-Briggs and DISC focus primarily on behavioural preference and personality type, SDI focuses on motivation and what drives the behaviour. This makes it more useful for conflict and repair conversations, because it allows people to say: I understand what you were trying to achieve, even if the way it landed was difficult for me. That shift, from judging behaviour to understanding motive, changes the quality of the conversation significantly.
5. What to try next
How it is used in Kate's work
SDI is most useful not as a self-awareness exercise but as a shared team language. When a team understands its combined motivational profile, it can have more honest conversations about why specific dynamics keep repeating: why meetings get stuck, why certain relationships carry friction, why feedback between particular people never quite lands. It creates a vocabulary for the behaviour that removes blame from the conversation and puts curiosity in its place.
6. What to notice
A small habit to try
The next time you find yourself frustrated by a colleague's behaviour, ask: what are they most likely trying to achieve here? Not what is wrong with them. What are they trying to protect or create? That question moves you from reaction to understanding faster than almost anything else.
Understanding why someone behaves as they do under pressure changes the conversation from judgement to curiosity. That shift is where trust starts.
7. What to design around the role
Three things tend to make a more substantial difference.
Use MVS to understand motivation before judging behaviour
Use SDI to understand what people are trying to protect or achieve.
Notice overdone strengths under pressure
Notice when a strength has become too much of a good thing.
Compare profiles before important conversations
Compare motives before assuming intent.
Use conflict sequences as early warning signs
Use the language to plan better conversations, not label people.
8. Questions to reflect on
Use these to notice where editing has become the default.
- 01What motive might be driving this behaviour?
- 02Which strength becomes overdone under pressure?
- 03How might my communication land differently for their MVS?
- 04What conflict cue should I notice earlier?
Takeaway
SDI is most useful not as a profile to carry but as a shared language for the moments when strengths get in the way of each other. That language makes the difficult conversation less personal and more productive. **Key terms** - **Motivational value system:** The underlying motive that drives a person's behaviour in relationships, whether concern for people, results, or process. - **Overdone strength:** A genuine strength that has passed the point of usefulness under pressure, becoming a source of friction rather than contribution. - **Relationship Awareness Theory:** The theoretical foundation of SDI, developed by Elias Porter, which holds that behaviour is driven by underlying motives rather than fixed personality traits.
Keep the next step clear.