Apsychologist plans to study the development of "intelligence" and his primary concern is whether he will actually study intelligence rather than another phenomenon, such as "reading fluency." to address this concern, he must ensure:

validity

Explanation:

The concern on setting a valid test to address the level of intelligence hs been an ongoing debate ever since IQ tests appeared:

For most people today there is a consensus that a general intelligence factor exists, and to measure it, a reliable test needs to be consistent over time and also show validity to be able to measure intelligence rather than "reading" "memory" or others side components of intelligence.

The IQ tests are today starting to take into account several formulas for also measuring the social and emotional components of intelligence.

answer; ///first they would cross the atlantic ocean, and end up either in europe or africa; good luck