Before revision:  Statistical models have only found minor regularities and anomalies. Other approaches have failed or are illusory. To this day, the physicists and mathematicians working in economy consider that the evolution of security prices is basically random, and, thus,  not predictable.
After revision:  Statistical models have only found minor regularities /anomalies, and other mathematical and physical approaches do not work. This leads researchers to consider that the evolution of security prices is basically random, and, thus, not predictable.