Yes, STUDIES is a Scrabble word!

Letter values in Scrabble US: S 1, T 1, U 1, D 2, I 1, E 1, S 1.

Is it a valid word?

STUDIES is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a detailed critical inspection
applying the mind to learning and understanding a subject (especially by reading)
a written document describing the findings of some individual or group
a state of deep mental absorption
a room used for reading and writing and studying
a branch of knowledge
preliminary drawing for later elaboration
attentive consideration and meditation
someone who memorizes quickly and easily (as the lines for a part in a play)
a composition intended to develop one aspect of the performer's technique

consider in detail and subject to an analysis in order to discover essential features or meaning
be a student; follow a course of study; be enrolled at an institute of learning
give careful consideration to
be a student of a certain subject
learn by reading books; I must hit the books now"
think intently and at length, as for spiritual purposes

Also: written report, subject area, subject field, field of study, hit the books.