A Brief History of the Strong®

President and Chief Career Coach


History of the Strong Interest Inventory

The Strong Interest Inventory, which is used to help people choose careers that will be satisfying for them, is perhaps the most well researched and well documented career assessment in the world.

This is a quick history of the Strong, including how it was eventually integrated with Dr. John Holland's RIASECs theory of careers and the infamous Holland Code.

For a more complete history of the Strong and the Holland system please see the Strong Interest Inventory Manual available from CPP.


1927 E.K. Strong Jr. Develops the First "Strong" at Stanford

Dr Strong first developed his assessment using empirical data rather than theory.

He tested people from several different career fields to identify what things they were interested in. These people had been in their career for at least 3 years and were satisfied with their careers.

When he analyzed the data he found clear patterns that showed people in similar careers had similar interests. For example, engineers would have interests in common with each other. Law enforcement professionals would have interests in common with each other.

Thus if you were to take his assessment, he could look at your interests and say that you have interests similar to lawyers and artists, so maybe you should look into those two career fields. That's how it worked.

Remember the point of any career test is to simply give you ideas for careers. It's up to you to then research these ideas to find the best fit. There are no career tests that will narrow down your choices to the one perfect career.

The main thing that stands out from his early work is that they used a lot of statistical analysis to separate out the meaningful patterns from those that were not relevant.

Today, if you take the training to become certified in administering the Strong, you will spend a lot of time reading and understanding the statistics which demonstrate how the Strong system has been proven to be both reliable and valid.

1974 The Strong Integrates Holland's RIASEC Theory

Up until 1974, the Strong Interest Inventory did not have an underlying theory other than how people with similar interests might like the same careers.

Along comes Dr. John Holland who developed the underlying theory, which is quite simple. Holland noticed that all types of work could be divided up into one of six basic types of work. He gave each type a letter (R-I-A-S-E-C) and a one word descriptive name. These are themes or patterns.


Career Type Diagram


Artistic Theme

Creative expression including writing, painting, sculpting, drama and dance

Social Theme

Helping people, care giving, teaching, working with teams and groups

Enterprising Theme

Selling, managing, persuading, business, leadership

Conventional Theme

Organizing, keeping track of things, data, accuracy, precision, details, repetition

Realistic Theme

Building, repairing, working outdoors, working with your hands, physical work, working with tools and things, including computer hardware and machinery

Investigative Theme

Gathering information, analyzing and interpreting data, working with ideas, theories, and concepts



Actually every career can be categorized by using one of these letters, or a combination of two or three of the letters.

Thus the Holland Code for someone who loves doing taxes and accounting is "CI."

The Holland Code for someone who enjoys Computer Programming and INformation Systems is "CIR."

The Holland Code for Human Resource Managers is "SE."

Actually, in the Strong system, they don't use the term Holland Code. Instead they use "General Occupational Theme" or GOT.


2004 / 2012 Update to Add Newest High Tech Careers

The Strong has an army of psychologists, statisticians, and career counseling experts who continually keep it revised and up to date as new careers appear in the work place.

Every time they do a major update, they actually have to go out and re-sample the working population. It's a lot of work.

The latest revisions added several new careers, while removing many others.

A few of the occupations that were added are:

  • Computer Programmer
  • Human Resource Specialist
  • Personal Financial Advisor
  • Secondary School Teacher
  • University Faculty Member

A few occupations that were updated:

  • Attorney
  • Computer IS Manager
  • Financial Manager
  • Marketing Manager
  • Software Developer
  • Registered Nurse
  • Human Resource Manager

And to make room for the newer occupations, as well as to account for changes in job titles, they removed several careers. Here are just a few:

  • Banker
  • Bookkeeper
  • Corporate Trainer
  • Top Executive
  • University Professor

Please note that having a career removed from the Strong does not mean the demand for that job is gone. Usually the job titles change in the real world and the Strong keeps up with that. For example, University Professor was removed but University Faculty Member was added.

However, if your career is on the delete list, it's a good reason to look into what the future demand for your job is. The people who revise the Strong do take into account which occupations are becoming more popular and which are beginning to fade away.

For a complete list of these changes, see the Strong Interest Inventory Manual Supplement, pages 3-4.

The Strong is A Psychometric Assessment

The Strong is so much more than just an interest matching tool. It is a complete Psychometric Assessment that covers things about your personality:

  • Your Personal Work Style - prefer to work alone or prefers working with and helping people
  • Your Leadership Style - more take charge or more lead by example
  • What your Learning Style is - more academic or more hands on
  • Your preference for Risk Taking - prefer to play it safe or enjoys new ideas and taking chances
  • Your Team Orientation - do you prefer to solve problems on your own or do you prefer collaborating on team goals

Because the Strong is a Psychometric Assessment, its use is restricted to those people who are trained and certified to administer it. We at CareerPlanner are of course trained and certified.


Career Counseling and the Strong

You can also purchase the Strong as part of a complete Career Counseling Package.