I've seen quite a few different implementations of this, ranging in scope from very focussed QA stuff through to quite broad overall performance monitoring.
The former could simply be e.g. % deliveries in spec, number of complaints/rejections raised and/or proportion of batches/orders resulting in a complaint.
For something more comprehensive you could broaden this out to more parameter-level detail, depending on the type of raw material specifications you're working with - e.g. if you use target ranges and a broader "acceptable" tolerance (or e.g. green/red/amber scoring) then they'd be obvious elements to consider.
Depending how much buy-in you have from other departments, you could also expand to e.g. deliveries on time, deliveries over/under weight etc.
Really depends how deep/broad you want to go with it.