I'm trying to determine the edge someone has (or in this case lack of edge) but I want to be precise in my analysis, at least from the assumptions I'm making. Take NBA.
1) So let's say someone has +.2 line value on sides. I'm not quite sure what I'm doing but can I do this? I'm going to ballpark a side at 3.8% so I simply take 3.8 x .2 and that's .76. So do I project that they will hit 50.76% going forward??
2) I'm not sure how this method relates to the above but lets say I have 51 plays and based on the SBR calculator I assess that 27 plays have 1.72% edge, 15 play have -6.48% edge and 9 plays have -2.38% edge. (I just kind of played around and taking an NBA spread of 8 I put "-105" into the 7.5 column to demonstrate the plays that closed a halfpoint good and got 1.72%; for the bad plays that closed a halfpoint bad I put "-105" into 8.5 and got -6.48% and then for the no moves I put "-105" into the 8 and got -2.38%) So I'm assuming reduced juice here.
Then I take (27 x 1.72) + (15 x -6.48) + (9 x -2.38)= 46.44 + (-97.2) + (-21.42) = -72
-72/51 plays = -1.4% per play
Any idea if these are good techniques, how 1 and 2 go together?
For question 2, I converted all your edges to decimal and compared to the -105 lines (and implied probability) you were betting and arrived at a total cumulative edge of -1.6% over 51 plays; which is likely the same conclusion you came to but due to rounding and approximations made in the calculations.
Question 1, what do you mean by "ball parking a side at 3.8%"