IQ test scoring has been fairly standardized since the early 1900s. The Stanford-Binet test established a process for measuring and interpreting intelligence that is still used and respected today.
IQ — or intelligence quotient — tests have been designed to reflect a person’s intellectual capabilities. They primarily predict a person’s ability to do well in an academic environment. Intelligence test scoring doesn’t take into consideration a person’s other talents — say, musical abilities, physical skills, social abilities or artistic talents. They solely measure an individual’s aptitude for answering a series of questions designed to test their reasoning, logic and comprehension.
The original IQ tests of the early 1900s were designed to give children a mental age that could be compared with their chronological age. Children who achieved higher IQs were recognized as having greater potential for pursuing education. Educators were then able to ensure that they had assistance in reaching their full potential.
A high IQ isn’t a guarantee of a successful academic career, a lucrative job or even personal happiness. But it does show an individual’s potential for performing well in an academic environment.
How Are IQ Test Scores Calculated?
Classic IQ tests ask a series of questions designed to test an individual’s logic and reasoning abilities.
The classic method for calculating IQ is:
Mental Age/Chronological Age x 100
With traditional IQ test scoring, 100 is considered to be an average score. Anything less than 90 is considered below average, while anything about 130 is considered superior.
Another way of measuring IQ is to put scores into percentiles. The 99th percentile reflects an IQ of 130, meaning only 1 percent of the population would have a higher IQ test score. An IQ of 100 would be at the 50th percentile — the IQ test score average.
Someone with an IQ of 120 is at the 91st percentile, meaning that only 9 percent of the population would score higher on an IQ test. Conversely, someone with an IQ of 70 is in the 2nd percentile, meaning 98 percent of the population would score higher.
The standard deviation for intelligence test scores is 15. This means that any score within one standard deviation – or 15 points – of a score of 100 is considered normal.
The range of 85-115 would all be considered normal, while two standard deviations from normal – say, 70 – would be considered low, while 130 would be considered high.
Overall, experts suggest that 95 percent of the population has an IQ that falls between 70 and 130 points.
Studies have shown that intelligence test scores will rise between 5 to 25 points during a generation — a phenomenon called the Flynn Effect. As a result, tests are revised every 15 to 20 years to take this into account. That way, a result of 100 remains the average, continuing to reflect normal intelligence.
You can find some great information on the Flynn Effect and its impact on IQ test scores here.
What Do IQ Test Scores Measure?
IQ tests are designed to measure a person’s skills in understanding concepts, as well as problem solving. A person’s ability to see relationships between things, as well as remembering information and patterns, are also reflected in their score. Abilities measured by the test include:
Spatial perception – ability to visualize the manipulation of various objects and shapes
Mathematical skills – talent in solving math problems, and in using logic
Language skills – ability to recognize patterns in words or sentences
Memory – ability to recall information The most effective IQ tests measure people’s abilities in a variety of areas, and aren’t limited to specific areas of intelligence.
It’s important to remember that a high IQ test score isn’t a guarantee of a successful life. Many other factors, including results from emotional IQ tests can be significant factors in predicting your future successes.
Still, IQ test scores do correlate strongly to career choices. As a general guideline, you can expect to do well in the following careers if you have an IQ within these ranges:
Farm Labourers: 75 to 125
Carpenters: 75 to 110
Construction Workers: 70 to 110
Police: 80 to 110
Accountants: 85 to 120
Clergy: 90 to 120
High School Teacher: 90 to 125
College Professor: 95 to 125
Lawyers: 95 to 125
Medical Doctor: 100 to 130
It’s important to remember that there are many factors that can influence intelligence — and the way we manage it. Age, gender, cultural issues and even learning strengths and disabilities can affect how we interpret and measure intelligence.
The diagnosis of something like Attention Deficit Disorder/Attention Deficit Hyperactivity Disorder (ADD/ADHD) can affect how we view a person’s potential — sometimes, unfairly.