The Aroon system was developed by Tushar Chande to highlight the start of a new trend and to measure trend strength. The Aroon indicator consists of two lines, 'Aroon(up)' and 'Aroon(down)'. It takes a single parameter which is the number of time periods to use in the calculation. Aroon(up) is the amount of time (on a percentage basis) that has elapsed between the start of the time period and the point at which the highest price during that time period occurred. If the stock closes at a new high for the given period, Aroon(up) will be +100. For each subsequent period that passes without another new high, Aroon(up) moves down by an amount equal to (1 / # of periods) x 100. See also AroonOsc.