Assessment, Statistics, and Research

  The concept of average intelligence is sometimes difficult to appreciate because the two words, average and intelligence, are sometimes not defined. Average   To psychologists and counselors who administer tests of intelligence, a person who scores at the 50th Percentile has average intelligence as defined by the number of correct answers to test tasks compared to others in their age group. Many tests set the middle score at 100 thus, 100 = average intelligence on many tests. All test scores vary from time to time so, a person may earn more or less points on another day. This fluctuation is estimated and can range for example by plus or minus 3-5 IQ points depending on the test and age group.  If you retake the test in a month or so, you may score better because of the “practice effect”—you’ve seen the items recently so you will probably do better. There is an average range so examiners will not focus on the obtained score but consider a broader range. For example, some...

Intelligence tests (IQ tests) are in the news lately as people banter about terms from many decades ago. IQ tests are widely used because they measure the ability of people to solve various problems, predict academic achievement, and help with job placement in some settings. The tests also help neuropsychologists assess functioning in people with impairments due to head injuries and brain diseases. During part of my childhood, I passed a facility where American IQ testing began. I saw people on swings and on the grounds of the Vineland Training school in Vineland NJ. It turns out that a little over 100 years ago, American psychologist, Henry Goddard, brought a test by French scientist, Alfred Binet , to the New Jersey Training School for Feeble-Minded Girls and Boys in Vineland, NJ. The test was modified and widely used in the U.S. What tests are used today? Today, a number of tests are available in the US and elsewhere. Popular American tests are the Wechsler Intelligenc...