Algorithmic Trading can be a complex subject. Keep your knowledge current with this glossary of key concepts, terminology, and technical indicators.
Imagine that the advance/decline index on the S&P 500 is currently at 1835. If at the end of the last trading day, 300 stocks were up (advance) and 200 were down (decline), 100 would be added to the advance/decline index value, pushing it to 1935.
When this index is plotted on a chart, it is known as the "advance/decline line".