TSF, the Time Series Forecast indicator, consists of linear regression measurements using the Least Squares method. Linear regression is a statistical tool for forecasting future Forex market values comparing to past values. TSF tries to forecast the following Forex market value. For that purpose, it defines the trend's upward or downward declivity and stretches those results into the future. For instance, when prices are moving upwards, TSF tries to define the upward declivity of the price compared to the ongoing price and stretch that calculation forward.

The trend is considered down when the Forex market price falls below the indicator, the Trend is considered up when the Forex market price rises over the indicator. Besides, a lot of analysts think that once prices shift above or fall below the indicator line; prices will likely move back to the line. The TSF indicator also defines if a change in direction happened monitoring the ongoing trend.

The Time Series Forecast indicator resembles the Linear Regression indicator with the exception of two important distinctions. One distinction is the default Length input value used for the TSF is much shorter because the plot line is stretched forward. Another distinction is that TSF plots its line forward, to the right of the chart, by the number of bars specified by the Bars Plus input. A larger Length input would not be as trustworthy as a shorter-term length while analyzing price activity and trends and would form a considerably exaggerated plot.

 Read More here