Intelligence: It is the capacity to understand the world, think rationally, and use resources effectively when faced with challenges. .
Why measure intelligence? In the early 1920s, IQ tests were used to keep certain immigrant groups from the United States. In the early 1930s, scientists began testing identical twins separated at birth to see if their environments cause them to score differently. They are hampered by the scarcity of test subjects and the fact that many had similar upbringings even though they were raised apart. The first legitimate intelligence tests were developed by Alfred Binet (1857-1911). Standardized intelligence test scores (IQs), which reflect a person's standing in relation to his or her generational peers, are based on tests that measure a number of different abilities. .
Psychometric testing, the use of standardized tests to assess specific abilities, has generated the most systematic research though many questions remain unanswered. IQ, a score that takes into account an individual's mental and chronological ages. Intelligence test scores partially predict individual differences in school achievement, such as grade point average and number of years of education that individuals complete. Test scores also correlate to some extent with measures of accomplishment outside of school, for example adult occupational status. This correlation is linked with school achievement because, in the United States today, high test scores and grades are prerequisites for entry into many careers and professions. These tests are also identified as Aptitude Tests/ Achievement test; which is used to predict a person's ability in a particular are or line of work. .
Although in theory the distinction between aptitude and achievement tests is precise, it is difficult to develop an aptitude test that does not rely at least in part on past achievement (Sternberg, 245). There are however, sacrifices made in group testing which, in some cases, may outweigh the benefits.