# TRIN This strategy was taken from chapter 12 of [*Short Term Trading Strategies That Work*](https://moshferatu.dev/moshferatu/short-term-trading-strategies-that-work) (2008) by Larry Connors. It is based on the short-term trading index (TRIN), also known as the Arms index. The formula for calculating the TRIN of an index is as follows: ``` TRIN = (Advancing Stocks / Declining Stocks) / (Advancing Volume / Declining Volume) ``` ---