The MBTI® instrument measures personality preferences on four different scales:

1. FOCUS OF ATTENTION
   Extraversion (E): Energized by people and things in the external world.
   Introversion (I): Energized by ideas or impressions in the inner world.
2. INFORMATION INPUT
   Sensing (S): Gathers details and facts that can be confirmed by experience.
   Intuition (N): Gathers ideas and sees future possibilties.
3. DECISION-MAKING
   Thinking (T): Makes decisions by logic and analysis.
   Feeling (F): Makes decisions based on personal values.
4. LIFESTYLE
   Judging (J): Enjoys planning and deciding.
   Perceiving (P): Enjoys remaining open to new options.