Throughput

Hi, John brilliant lecture style thank you very much!
Can I ask a question, page 16 of the notes, it says
“In a just in time environment we should be attempting to eliminate inventories. Use of a limited resource in production of inventories should be avoided and therefore any work in progress should be valued at only the material cost”

Does this mean that there will be no WIP element of a throughput accounting question?
Either way, does this statement mean that throughput accounting only takes into account what resources are available after production of inventory or does it assume that a company does not produce its own inventory at all?..I guess I don’t fully understand the statement!

Cheers