Something to think about (4)
(Other definitions for iq test that I've seen before include "Psychometric measurement of intelligence" , "Measure of intelligence quotient" , "'A measurement of intelligence (2,4)'" , "Intelligence trial" .)
'something to think about' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for idea that I've seen before include "Plato's Form is" , "intellectual product" , "Inkling" , "Notion, concept" , "It comes to mind" .)