Integrative complexity is a research psychometric that refers to the degree to which thinking and reasoning involve the recognition and integration of multiple perspectives and possibilities and their interrelated contingencies.
Integrative complexity is a measure of the intellectual style used by individuals or groups in processing information, problem-solving, and decision making. Complexity looks at the structure of one's thoughts, while ignoring the contents. It is scorable from almost any verbal materials: written materials, such as books, articles, letters, and transcript; as well as audio-visual material.
The measure of integrative complexity has two components: differentiation and integration. Differentiation refers to the perception of different dimensions when considering an issue. Integration refers to the recognition of cognitive connections among differentiated dimensions or perspectives.
In a 1988 study it was demonstrated that changes in Integrative Complexity could be potentially used in international violence prediction. These findings were seen again a 1995 article by Guttieri, Wallace, and Suedfeld looking at the Cuban Missile Crisis.
Evaluative differentiation involves the acknowledgement that reasonable people can view any given event differently and that making a decision involves balancing any legitimate competing interests. In contrast, thinking in an evaluatively un-differentiated manner involves thinking rigidly and refusing to compromise or consider any alternative.
Conceptual integration uses reasoning that builds upon earlier evaluative differentiations. It is commonly used to help give context to previous evaluative differentiations. For example, it could take the form of explaining why someone may view an event in a different way or in what ways a compromise could be made between conflicting values. 
Integratively complex thinkers are better able to reach mutually advantageous solutions in mixed-motive games than integratively simple thinkers.  Declines in integrative complexity in diplomacy during times of crises is also a lead indicator of war, while increases in integrative complexity is a lead indicator of reaching compromise agreements that avert war. 
Integrative complexity can also have drawbacks. Thinking in an integratively complex way, for example, makes one more prone to suffering from the dilution effect  Integratively complex thinkers are also more prone to defer to others or put off making a decision when faced with difficult cost-benefit decisions.  Additionally, while integratively complex thinkers are more likely to reach a mutually advantageous compromise when dealing with reasonable opponents, unreasonable opponents are much more likely to be able to exploit them. 
- Suedfeld's Integrative Complexity Research
- Changes in Integrative Complexity Prior to Surprise Attacks, J. of Conflict Resolution 32(4) by Suedfeld and Bluck (1988).
- The Integrative Complexity of American Decision Makers in The Cuban Missile Crisis, J. of Conflict Resolution 39(4).
- The Slavery Debate in Antebellum America: Cognitive Style, Value Conflict, and the Limits of Compromise.
- Development of integrative solutions in bilateral negotiation.
- Integrative complexity of communications in international crises.
- Cognitive Style and Political Ideology.
- Integrative Complexity of American and Soviet Policy.
- Accountability and Judgement Processes In a Personality Prediction Task.
- Accountability: a social magnifier of the dilution effect.
- Accountability amplifies the status quo effect when change creates victims.
- Psychological Perspectives on Nuclear Deterrence.