Chelsea's young squad is learning in public

A squad assembled this young was always going to produce results that swing between the two extremes, and this season has obliged.

The trade being made

Signing players at the start of their peak rather than in the middle of it lowers the fee and raises the variance. Both halves of that bargain are now visible week to week.

You cannot buy potential and then complain about inexperience.

The more useful measure is whether the performances trend upward across a season rather than whether they are reliable within a month.