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History and development of the SDI 2.0

Tim Scudder, PhD

Tim Scudder, PhD

24-page report

Author’s Note

I have been working full-time with the SDI since 1995 and have contributed to its development and utility through research, authorship, and application. Given my role, people often ask if I am the founder or creator. I am not. That distinction rightly belongs to Elias Porter, or “Port” as his friends called him. I have assumed the mantle of SDI development, and someday that mantle will pass to someone else. I never had the opportunity to meet Porter, but I do know one word that says a lot about him: Blue (shorthand for his Altruistic-Nurturing Motivational Value System). He wanted to help people and was not overly concerned about getting credit for his work. The more I learned about him, his Relationship Awareness Theory, and the SDI, the more I became convinced that his modesty and desire to help others succeed caused him to become an overlooked figure in psychology.

This is the story of the SDI 2.0, so named to reflect its evolution since Porter created it. The SDI 2.0 is now a single assessment that produces four interrelated views of a person:

  1. Motivational Value System – a personality type when things are going well.
  2. Conflict Sequence – a personality type when experiencing conflict.
  3. Strengths Portrait – a ranking of productive strengths used at work.
  4. Overdone Strengths Portrait – a ranking of non-productive strengths used at work.

But this is not just a story of a product; it is a story of people interacting with each other and the social forces of their times. I am both the narrator and an actor in this story. I use the first person when I narrate my own involvement or add personal observations. I wrote this article because I realized that I was the sole keeper of an “oral history” of the SDI. I wanted to commit the facts to writing, and hoped that the story would be interesting for anyone who uses the SDI 2.0. Let’s rewind the clock a bit and get started.

Ancient History

The SDI 2.0, like all modern personality assessments, rests on the conceptual foundation laid by earlier societies and theorists. The idea of personality types is hardly new. Ancient Chinese society described personality types based on the year of birth. Mesopotamian society provided the 12 signs of the zodiac, which astrologists use to describe personality differences based on the day of birth. Various religious texts describe gifts from gods, many of which are like personality characteristics. In multi-theistic traditions, the gods themselves have distinctly different personalities. Long-established caste and other hierarchical social systems describe differences in people based on birth circumstances, such as being an untouchable or having royal blood. The Greek philosopher Hippocrates ascribed four personality types to the effects of varying levels of different bodily fluids (blood, bile, etc.). His four temperaments are still used, albeit in revised or renamed versions, to describe differences among people despite the fact that his biological assumptions were incorrect.

Compared with those ancient practices, the idea of psychometrics – using standardized measurement techniques to describe differences in personality – is quite recent. Modern psychometrics still rely on human-created theories and concepts, but most are supported by rigorous scientific theory and methods. That is, they are evaluated against objective standards of reliability and validity, not solely by their face-validity or popularity.

(This is an excerpt from our History and Development of the SDI 2.0.)

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