Maybe you wouldn't - my thought was that (to exaggerate) if company A produces 10 vehicles and issues 5 recalls, whereas company B produces 1,000,000 vehicles and issues 10 recalls, then company B isn't doing twice as badly as company A despite issuing twice as many recalls, because they've manufactured 100,000 times as many vehicles, and we probably need to factor that in somehow. Likewise the number of vehicles affected by each recall.

As the other commenter said, I also think number of SKUs is important as each one represents a different design and BOM.