Data Snooping
Data snooping, also known as data mining bias, happens when a researcher tests many hypotheses on the same dataset until a statistically significant result is found. This is a significant issue in financial research because it can lead to the discovery of patterns that are purely coincidental.
Once a "significant" result is found through snooping, it is often assumed to be a valid strategy, but it usually fails when applied to live markets. To combat data snooping, researchers must maintain strict separation between the data used for model development and the data used for final validation.
It is a deceptive practice that can undermine the credibility of quantitative research. Maintaining integrity in the research process is paramount for developing reliable trading systems.