Original sentence: A study on the Maharishi Effect published in 1999 in the journal, Social Indicators Research, suggested that there was a correlation between the gathering of a group of 4,000 participants in the Transcendental Meditation and TM-Sidhi programs in the District of Columbia, and a reduction in violent crime in that city
Edited sentence: A study on the Maharishi Effect published in 1999 in the peer-reviewed  journal Social Indicators Research suggested that there was a correlation between the gathering of a group of 4,000 participants in the Transcendental Meditation and TM-Sidhi programs in the District of Columbia, and a reduction in violent crime in that city