I'm not an MDX guru but, what you posted is not the complete MDX code. The complete statement would include (at least) a SELECT and an ON statement. The "Average...

This seams pretty simple; what have you tried so far? Where are you stuck?

Dang! Ed beat me to it. 

I would add - for optimal performance you want this index in place: 

CREATE INDEX nc_poc_employees_level ON dbo.employees(OrganizationLevel);

I dont know of any great SSRS books but The Microsoft Press book, SSRS Reporting services is fine. For me SSRS is the kind of thing I learn more by...

I created a function called SubstringBetween8K which was designed for exactly this type of problem. It uses NGrams8K. Here's the function:

CREATE FUNCTION [dbo].[substringBetween8K]

I've been away for awhile wrapping up a project with some hard deadlines but that's all done and I'm back.

Jeff Moden's DelimitedSplit8K is the best in the business on pre-2012 systems and non-max data types; on SQL 2012+ I suggest DelimitedSplit8k_LEAD by Eirikur Eiriksson which is based...

I learned something new today: # is a valid temp table name.

CREATE TABLE #(id int);
INSERT # VALUES (1);
SELECT * FROM #;
DROP TABLE...