At Their Best
People with ISTP preferences carefully observe what is going on around them. Then, when the need arises, they move quickly to get to the core of a problem and solve it with the greatest efficiency and the least effort. They are interested in how and why things work but find abstract theories uninteresting unless they can quickly apply them. They often function as troubleshooters. 

ISTPs resist regimentation and rules, thrive on variety and novelty, and enjoy the challenge of solving a new, concrete, extensive problem. 

ISTPs can be considered the Practical Analyzers. They use Introverted Thinking (Ti) as their core approach to work and living. ISTPs usually take a calm, objective, logical approach. They tend to enjoy investigating and analyzing situations. 

Practical Analyzers thrive in situations where they can spot flaws and figure out solutions to problems. They often want to work independently and solve practical problems. If you are a Practical Analyzer, you are likely at your best when you are logically evaluating data. To gather more information, Practical Analyzers observe situations and pay attention to concrete facts and realities. This realistic approach to the world provides input for a more accurate and thorough analysis of facts. Others usually see the ISTP using this secondary, flexible approach. They may glimpse the more private, examining side of the ISTP by observing their somewhat detached interactions or their sometimes cynical or sarcastic humor.

Characteristics of ISTPs
ISTPs use their Thinking primarily internally to see the essential structure underlying the facts. Their minds seem to work almost like computers, organizing data, reasoning impersonally and objectively. They make rational decisions based on a great deal of concrete data. ISTPs are likely to be:
  • Detached and objective critics 
  • Analytical and logical problem solvers 

ISTPs are realists, focusing on what is and what can be done with it, rather than on theoretical possibilities. They are often creative at dealing with the immediate problems and goods at hands-on tasks. ISTPs are: likely to be:
  • Practical and realistic 
  • Factual and pragmatic 

ISTPs are expedient and believe in economy of effort – doing only what is needed with the last possible discussion and fuss. Their focus is on getting the desired results. 

ISTPs are typically practical ANALYZERS; value exactness; more interested in organizing data than situations or people; reflective, cool and curious observers of life. Having Introverted Thinking as their strongest mental process, they are at their best when analyzing experience to find the logical order and underlying properties of things.

They typically value:
  • A reserved outer life
  • Having a concrete, present-day view of life, clear
  • Clear, exact facts (a large storehouse of them)
  • Looking for efficient, least-effort solutions based on experience
  • Knowing how mechanical things work
  • Pursuing interests in depth, such as hobbies
  • Collecting things of interest
  • Working on problems that respond to detached, sequential analysis and adaptability
  • Freedom from organizational constraints
  • Independence and self-management
  • Spontaneous hands-on learning experience
  • Having useful technical expertise
  • Critical analysis as a means to improving things

How Others May See Them
ISTPs are egalitarian and generally tolerant of a wide range of behavior – until their ruling logical principles are attacked. At that point, they can surprise others by expressing their firm and clear judgments. ISTPs listen and seem to agree because they are not disagreeing; later, others may find the ISTP was analyzing and making internal judgments. 

With their constant scanning for information and focus on results, ISTPs will change course readily if they see another, more efficient way. Because of this, others sometimes have trouble “reading” them. They tend to be quiet and reserved, though they can be quite talkative in areas in which they have a lot of knowledge.

Others usually see ISTPs as:
  • Adaptable, action-oriented risk takers 
  • Confident, independent, and self-determined  

Potential Areas of Growth
Sometimes life circumstances have not supported ISTPs in the development and expression of their Sensing and Thinking preferences.

  • If they have not developed their Sensing, ISTPs may have no reliable way of getting accurate data about the external world or of translating their thoughts into action.
  • If they have not developed their Thinking, they may get caught up in the realities around them and not take time to do the internal logical processing they need to make good decisions. Then their actions may be haphazard responses to immediate needs. 

If ISTPs do not find a place where they can use their gifts and be appreciated for their contributions, they usually feel frustrated and may:
  • Become cynical and negative critics 
  • Withdraw their attention and energy 
  • Postpone decisions 

It is natural for ISTPs to give less attention to their non-preferred Feeling and Intuitive parts. If they neglect these too much, however, they may:
  • Overlook others’ emotional needs and values 
  • Not give sufficient weight to the impacts of their decisions on others
  • Focus on intently on immediate results that they lose track if the long-term ramifications of their decisions and actions 

Under Great Stress
Under great stress, ISTPs may erupt outwardly in inappropriate displays of emotion. The resulting explosive anger or hurt tearfulness is quite unnerving to others and embarrassing to the usually calm and controlled ISTP.
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Sources
Introduction to Type, Sixth Edition developed by Isabel Briggs Myers

MMTIC®Murphy-Meisgeier Type Indicator for Children developed by Charles Martin, Elizabeth Murphy, and Betsy Styron

Donna Dunning’s terrific blog