End game stats

As a Karma I always find myself wondering just how much of an impact my shields have had, numerically. No matter where I take her, the shields always feel exceptionally powerful (really feel that 60% ratio on Mantra shields), but is that my ego telling me "woo good job" or are they actually being that effective? I'm sure some other people who play champs that use shields probably wonder this too. Would we ever potentially see some sort of Damage Prevented statistic being tracked?