Some of the smartest people, as measured by conventional IQ tests, ultimately fail because they cannot stick to a given path or adjust easily to changing circumstances. Conversely, others who may not test well, but who have a strong will to succeed, may achieve unexpected excellence.

Test results for intelligence and cognitive ability, by themselves, are not the best indicators of future success. Time and again, such factors as motivation, determination, persistence and hard work have proven to be more important than theoretical assessments of a workers ability to overcome the inevitable barriers which might prevent him or her from becoming a high achiever.

IQ tests, some of which can be quite lengthy (unlike the quickies being offered by social media on the Internet), are based on a normal distribution sample in which the average persons score is set at 100. In most tests, 95 percent of the sample scores will be arranged from a low of 70 to a high of 130 along a bell curve, with about two-thirds falling between 85 and 115. By definition then, an IQ score of 130 is higher than 95 percent of others taking the same test. About 2.5 percent will fall below 70, which is considered the beginning of intellectual disability. Two of the most common tests are the Wechsler Adult and the Stanford-Binet Intelligence Scales. Both tests take 60 to 90 minutes to complete.

Jo Craven McGinty, a veteran data analyst and Pulitzer Prize winner, discussed IQ tests in a recent article in The Wall Street Journal. As she says, Measuring smarts is harder than it sounds. McGinty points out that, while such tests may be useful in identifying gifted or special-education children, similar tests for adults may not be as helpful. Her column quotes Dr. Kevin McGrew, director of the Institute for Applied Psychometrics, as observing that only 40 percent to 50 percent of student academic performance, for example, can be correlated with IQ tests. Dr. McGrew notes that the other 50 percent to 60 percent of performance cannot be explained by cognitive ability alone. Ms. McGinty also concludes that other qualities which are not measured in IQ tests play a significant role in achieving success. She sums it all up with a famous quote from Thomas Edison: Genius is 1 percent inspiration and 99 percent perspiration.

Some people are just not good at taking tests. Others may not have the background or language skills which were assumed when developing the fundamentals of a particular test. Others may be exceptionally good at understanding concepts and solving problems, but are disadvantaged by limited memory. Native intelligence cannot always be measured accurately by the kinds of standardized tests which are currently being utilized by many large companies.

Heres the bottom line: Using tests, particularly brief screening tests, to determine whether a worker is suitable for a certain position may well be a waste of time and may exclude some employees who could contribute significantly to your companys future profitability.

Jack Goodhue, management coach, may be contacted at goodhue@aol.com.