Holland codes

• Realistic (the doers): hands-on work with tools, machines, plants, animals and the outdoors, and a liking for things you can see and touch.
• Investigative (the thinkers): science, maths and research, working out how things work and solving problems by study.
• Artistic (the creators): design, writing, music, drama and other work where you make something of your own and are free to express yourself.
• Social (the helpers): teaching, caring, advising and working with people to help them learn, heal or get on.
• Enterprising (the persuaders): leading, selling, speaking up, starting things and taking a chance to get results.
• Conventional (the organisers): records, figures, schedules and clear rules, and work where care and accuracy count.

The labels in brackets are nicknames, not boxes. A person almost always likes some of each type, and what a type describes is a kind of activity, not a kind of person.

An interest inventory asks how much you would like many activities, adds up the answers for each of the six types and ranks the types. Your Holland code is the first letters of your top three, strongest first. A code of SAI means the social type came first, the artistic type second and the investigative type third: a person who likes helping others, making things and finding out how things work.

The order matters. SAI and ASI use the same three letters but put a different interest first, and the first letter is the one that says most.

Holland drew the six types as the corners of a hexagon, in the order realistic, investigative, artistic, social, enterprising, conventional. Neighbours on the hexagon have something in common: investigative and artistic both ask for ideas, social and enterprising both deal with people. Types that face each other across it, such as realistic and social, pull in different directions.

So a code whose letters are neighbours, like SEC or IAS, describes a fairly even set of interests, and a code with letters from opposite corners describes a person who likes quite different things. Neither is wrong.

Careers advisers use a Holland code to start a conversation. Many careers guides and databases list occupations with a code of their own, so you can look at jobs whose activities fit your top interests, including some you had not thought of. It is a way of widening a list, not of narrowing it down to one answer.

• Look at the activities behind your top letter and ask where they turn up in work, including work you have never heard of.
• Read two or three jobs that fit the code, and ask yourself which activities you would actually want to do all week.
• Take the inventory again after a few months: interests grow and change with what you try. For a different way of describing yourself, the Big Five traits are about personality and not about interests.

The career interest test lists 92 activities and ranks eight interest areas of its own: leadership, organization, altruism, creativity, analysis, production, adventure and erudition. It is built on the Oregon Vocational Interest Scales, a public-domain questionnaire^[1], and its areas are not the six Holland types.

Some of the names sound alike, but the two systems were built separately, and we do not turn one into the other, because that would be a guess dressed up as a result. That is why the test gives you your top three areas and never a Holland code.

The authors of that questionnaire published how 665 adults of a community in Oregon rated its areas^[1], and the test places each of your areas roughly beside them, in one of five levels. Those adults were older than most people choosing a career, which is why the test gives no rank and no share of people.

• It says nothing about what you are good at. You can enjoy the idea of a type of work without having the skills, and be skilled at something you do not enjoy.
• It does not predict that you will do well or be happy in a job. Pay, people, place, skills and chance matter as much.
• Two people with the same code can want very different lives.
• It is not a measure of personality, ability or mental health, and it is no basis for choosing a person for a job.