I am optimizing parameters by running simulations, each simulation processing 2012-2013. After each 'run' I come up with a return representing all the trades which the system took. For my GA, I am specifying initial population of 1000 individuals and I find out how each individual performs partly by inspecting how much money was made or lost for each of the 1000 simulations.Is it ok to use the return at the end of a simulation to calculate Sharpe ratio for the simulation, thus each 'Individual' gets a Sharpe ratio? My main concern is that a simulation is for whatever time period I get the data for, and that won't necessarily be a year, it may be 6 months or it may be 5-years.Thank you.

To clarify I would like to use all the trades within each simulation to compute my Sharpe. Thus the Sharpe would represent performance of the strategy.

The convention is to annualise so you can show your nice results to other people when looking to raise capital - but as long as all the simulations are for the same time period it is still an apples and apples comparison.

I am so thankful for your response and it will help me to move on. Thanks again!