Adjusting Aggression Stats For High VPIP

[gaming_mouse]

I know that low aggression stats can be deceiving for players who have very high VPIPs. But how deceiving? And how should I think about the adjustment?

From what I understand, the basic idea is that these players will have to call postflop with weakly kicked pairs and other marginal hands, so that even though they can be quite aggressive postflop they may appear passive (based on their stats). Is there more to it than that?

Is there any way to analyze this effect precisely? If not, what are some ballpark rules I should use?