Hi,

I've been trying to understand cEV but dont quite get it. Here is an example hand from big 1.10$ on stars. I know this is clear jam but HEM says cEV difference is -7369 and I cant work out how its calculated. Any help?

The cev diff is the difference from what you expect in the long run to what you actually get in a specific allin spot.
(If you replayed the exact situation thousands of times and averaged the outcome, say 99 vs ,the specific hand held by the opponent, in this case A9o).

Using Pokerstove the 99 vs A9o (all different suited) has 70.395% hand equity.

The equity is what we get back from an allin pot and is effectively telling us that every time we get this exact hand match allin preflop we get back 70.395% of the final pot, so it is a great bet here.

Although 99 is ahead it still loses 29.605% when things go wrong for it. In this hand you won the pot completely and so gathered up 29.605% of the pot you are not really entitled too compared to the long run, or in other words you got lucky to this amount. When HEM analyzed the hand you won all the chips and got 7369 more chips than you would expect in the long run so the difference to the expected and what you got was -7369 chips.

The cev diff for one hand by itself is not much use but if you gather enough similar hands together the result is useful as it smooths out some of the uncertainty when analyzing hands. If you look at the way you play AKo in 30bb to 50bb situations the cev adjusted value is a better estimate of your play.

The final pot was 24,892 chips and you won 24,892 * 0.29605 = 7369.2766 chips more than the expected long run for this match.