ISTJ’s (11.6% of the U.S. population) tend to be conservative people by definition of their type. Yesterday is the measure by which we can measure the future, and in the thinking of the ISTJ, past performance is the prime indicator of future success. Warren Buffett’s investing philosophy has little to nothing to do with future vision. It is based on companies that have a valuable product that people use and understand.

Warren Buffett, 83, “the wizard of Omaha,” chairman of Berkshire-Hathaway, is the richest and most popular ISTJ in the world (net worth just short of 100 billion dollars).

Warren Buffett, 83, “the wizard of Omaha,” chairman of Berkshire-Hathaway, is the richest and most popular ISTJ in the world (net worth just short of 100 billion dollars).

Buffett invested in the Dairy Queen fast-food franchise, because as a frugal person he liked the economical food offerings. Companies that Buffet invests in are selling under their value, and simple math makes them valuable.  He does not invest in high tech startups because they have no history and the product makes little sense

Unlike the INTJ, ENTJ, and ENTP, who have a future vision of space tourism or eyewear that reads you your emails, Buffett and other ISTJ’s don’t always doubt the possible value of those things, but they often don’t join in these efforts because they have no history.

The ISTJ’s Introverted Feelings function may mask the fact that they are often caring people who care very deeply about other people. Buffett has now designated that 99% of his wealth will go to the Bill and Melinda Gates Foundation, who are “dedicated to the idea that all people deserve the chance to live a healthy and productive life.” Yet in the act of giving to this foundation he makes a very ISTJ statement: “the Gates invented the wheel.” There is no need to reinvent it.

The people who don’t get along with the ISTJ often see that person as obstructionist. Why are we spending money on an unproven product? How do you know this equipment will do what it says? Sure, it’s urgent for your success, you say, but have you gone through the requisition process? Your immediate need does not obliterate the established rules of this organization.

Which are the types most likely to run afoul of the ISTJ?  It could be any one of them, depending on the situation, but INFJ’s have a vision that they often can’t explain to the ISTJ, who simply wants the data.  The INFP not only has a vision that he or she knows to be true regardless of data or what anyone else thinks, and often the ISTJ just isn’t buying this approach. The ENTJ has a strategy that is just about to gel, and the ISTJ stands firmly in the way of progress. The ENTP has found a loophole in the rules and has already bought the component he needs and is not returning ISTJ urgent emails.

Many people in an organization value the ISTJ for being the glue that holds the organization together. The ESTJ can deal with the ISTJ because both see the value of organizational structure, as well as most SJ types. The ISTJ can scold and seem negative, but they are the person who knows the facts, and everyone appreciates that.