What does SL-TDI measure?

Directly measures the introverted and extraverted expression of Sensing, Intuiting, Feeling and Thinking.

Fundamental to the SL-TDI is the assumption that "you cannot function without an attitude." That is, each of the four Type Functions (Sensing, Intuiting, Thinking and Feeling) are latent capacities requiring psychological energy for their expression. This energy or, in Jungian terms, attitude, is represented by introverting (psychological energy directed to the inner world of the individual) or extraverting (psychological energy directed to the external world of objects and conditions).

The SL-TDI is designed to directly measure the introverted and extraverted expression of all four Type Functions. These eight measures of personality expression are called Type Modes. By using this point of measurement, a host of complicated schemes and untested assumptions about the relationship between introversion and extraversion (when treated as autonomous and independent variables) and the four Functions (when they are also treated as independent variables) are no longer necessary and are completely eliminated.