Yes, GENERALIZATION is a Scrabble word!

Letter values in Scrabble US: G 2, E 1, N 1, E 1, R 1, A 1, L 1, I 1, Z 10, A 1, T 1, I 1, O 1, N 1.

Is it a valid word?

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

reasoning from detailed facts to general principles
an idea or conclusion having general application
the process of formulating general concepts by abstracting common properties of instances
(psychology) transfer of a response learned to one stimulus to a similar stimulus

Also: inductive reasoning, stimulus generalization, stimulus generalisation.