Obviously the big lucky streak at the beginning takes a while to even out. Ending at 29 rather than 23 BTC is a big difference.
What does the 29 and 23 BTC represent? Obviously the pool has earned a lot more than 29 or 23 BTC? Since nominal terms are meaningless (although some users might like to see them) it may be more useful to graph the difference between expected and actual recovery over time as a %. i.e. the ending point of 29 vs 23 would be +26%.
The second graph is what someone with 1% of the pool's hash power would have earned since the time we switched to PPLNS. Maybe +26% makes more sense, instead of picking some arbitrary hash power.
Nice graph. The title is a bit misleading, though -- instead of saying "PPLNS vs. Expected Average" it should probably say "Pool earnings vs. expected average". The higher earning came from pool luck, not from the reward method.
I felt it was wrong to call the second graph "actual earnings" because noone hashed at 1% of the hash power the entire time. It's a bit hypothetical. Maybe it's ok to call it actual earnings if I put percentages on it like DAT suggested.
Also, the graph is PPLNS vs PPS (for this specific pool for the time we've been using PPLNS). The higher earnings came from pool luck, yes. But it was paid out to miners because of PPLNS. In this case we were lucky and payout was higher than PPS. But it could of course have been the opposite. It shows the variance from PPLNS. And as we see, 46x difficulty is not enough shares to even this out.
In this case, with PPLNS, the +26% earnings from good luck went to the miners. If it was PPS it would have gone to the pool op. Same thing of course if it had been -26%. With PPLNS the miners get the variance, with PPS the pool op does.
Can you explain that last graph? How can you have cumulative earnings higher than the expected average without corresponding dips below the average? Seems like that would imply the pool is losing money (and a great deal of it if that graph is accurate).
That's just the pool having better than average luck for a while near the beginning.
What parameters did you use to generate the graph? What is the timeframe of the second graph...
The timeframe for both graphs is 46x difficulty number of shares. Which is a while at a 70 Ghps pool, but I guess only about a day on deepbit? You can see that every area with zero pay in the first graph leads to a flat line in the second graph where earnings don't increase. Everything matches up between the graphs on the X-axis.
It would have made very much sense to mine here at the lucky period near the beginning, yes. But of course noone can predict that, and that's what makes PPLNS safe from pool hopping.