Abstract: Example trading systems and methods are described. In one implementation, a method allows a user to construct algorithmic trading strategies by presenting to the user components of algorithmic trading strategies. These components include declarative rules and expressions associated with algorithmic trading strategies, and the user constructs an algorithmic trading strategy using the declarative rules and expressions. An algorithmic trading strategy is tested by compiling the performance of the algorithmic trading strategy against historical market data. The user also has the option to select a specific time interval over which to evaluate the performance of a constructed algorithmic trading strategy. The testing results are communicated to the user.