SAN FRANCISCO — Like most large law firm partners, Alexander Lee had heard grumbling from clients unhappy to be billed for work performed by first-year associates. So when the Paul Hastings tax partner set out to rethink associate training, he started there.

Lee spent several months talking to clients and called on colleagues to do the same, asking, as he puts it, “What’s going on? What are you saying when you say that first-years aren’t efficient? What is it, what are you seeing on the bill?”