Michal - To follow up on this this good thread can I seek some explanation from you on the following

I've been testing a new particular system and have the following outcomes.

Test Period: 2009 to 2011
5251 Bets - Profit $353.00 on NSW Tab

2nd Phrase of testing for 2012 - 13
2012 Shows a $400 loss
2013 Shows a $150 Profit ... back on track

Is there anything else system developers should be using to test the long-term profitable of a particular system. In this case... would you sack or back.

What other variables should be under consideration apart from sample size

Regards