Providing jury trial

Should all cases be tried by two separate juries? Or three? Or 12? Too expensive, at least if each jury has 12 members. Two juries of six members, or three juries of four members, would probably be an improvement over the present system. But isn't there some way of testing the relative merits of such alternative options, or of comparing the merits of trial by jury versus trial by judge? Yes, there is. It could be called Two Verdicts Concordance Test.