Traveller - the WISC (wechsler intelligence scale for children) is a cognitive assessment, so will assess his underlying intellectual abilities, across verbal, nonverbal, working memory and visual processing areas. It's an IQ test. But it's more complicated than just getting a single IQ score like you see on TV.

The WIAT (wechsler individual achievement test) is an assessment of academic skills. Reading, maths, written language and oral language. As they have been developed by the same people they can be compared to each other and used to assess whether the are learning difficulties as well as cognitive difficulties contributing to his difficulties at school.

It's good to get a battery of assessments like this. The psychologist will do it individually with him and separate from the classroom, so it is 1:1 and that can change behaviour etc, but does mean its the best conditions to get the best scores possible.

Then they will write a report combining all the information and make a call on what they think is happening, as well as provide recommendations. Every psych does thus differently though, so it depends on who you have as to what that will look like.

Happy to chat and advise more if you want to PM me.