Per Investopedia: The ASI is used to gage the long-term trend by comparing bars which contain its opening, closing, high and low prices throughout a period of time. It is a trend finding/confirming tool.
//Accumulative Swing Index //By Rob Pecoraro //Feel free to use it! //If you change it, improve it or alter it, just give me props in a comment! study("ASI", overlay=false) a = high - close[1] b = low - close[1] c = high - low L = input(30000, minval=1) K = max((high[1]-close), (low[1]-close)) TR1 = max(a, b) TR2 = c TR = iff(TR1>TR2, TR1, TR2) ER = iff(a > b, (high-close[1])-.5*(low-close[1])+.25*(close-open[1]), iff(b > c, (low-close[1])-.5*(high-close[1])+.25*(close[1]-open[1]),(high-low)+.25*(close[1]-open[1]))) SH = close[1]-open[1] R = TR-.5*ER+.25*SH si = 50*(((close-close[1])+.5*(close-open)+.25*(close[1]-open[1]))/R)*(K/L) asi = si[1]+si plot(asi, "Fast",black, 2)