Thanks George and Ron.
PositionScore = IIF(PS > WorstScoreHeld, PS, 0); The documentation says a "score of zero means no trade" and "exit the trade if there is already an open position" so this should do what I want. I spent some time learning the low level custom backtester procedure and am going to play with that also. I like the increased control and custom metrics available. The "AmiBroker Custom Backtester Interface.pdf" document in the files section of this group does a great job of explaining the interface: http://f1.grp.yahoofs.com/v1/oL_RRsKmYZ- ngC1kzVfj7In1N_zxN9IOReF4PJQtLQmzcFgucZ8uyyw_FU2QXTH3Ga0_OYVmLqaQTDAb A7ebS87qAFFyXKaUmME8NlQ2Ltw/AmiBroker%20Custom%20Backtester% 20Interface.pdf Thanks everybody for helping me get up the learning curve.
