This first intelligence test, referred to today as the Binet-Simon Scale, became the basis for the intelligence tests still in use today. However, Binet himself did not believe that his psychometric instruments could be used to measure a single, permanent, and inborn level of intelligence.

Binet stressed the limitations of the test, suggesting that intelligence is far too broad a concept to quantify with a single number. Instead, he insisted that intelligence is influenced by many factors, that it changes over time, and that it can only be compared in children with similar backgrounds.