Execution Timing Randomization

If a strategy always submits its orders at exactly 9:31:00 every morning, that regularity is itself information. Other participants — especially anyone watching order flow at high frequency — can learn the pattern and position ahead of it, effectively front-running a signal that was never disclosed directly. Execution timing randomization breaks this by adding a small random delay, or jittering the submission time within a window (say, uniformly between 9:30:00 and 9:33:00), so the exact moment of execution carries no information about the underlying signal.

There is a second, less obvious reason to randomize: backtests that always execute at a fixed time relative to a signal can pick up a spurious edge from that specific timing coinciding with some recurring microstructure pattern — a liquidity dip, a quote refresh, a scheduled data release — that has nothing to do with the strategy's actual logic. Randomizing execution time in the backtest itself, and checking that the measured edge survives, is a way to test whether the strategy's apparent profitability depends on hitting one precise clock time rather than on the signal generally being right.

A simple check: if a strategy backtested with orders always at exactly one second past a bar close shows a strong edge, but the same strategy with execution jittered by a few seconds either way shows the edge shrink substantially, that is a warning sign the original result was partly an artifact of that one timing choice rather than a robust signal.