In technical analysis a technical indicator is a mathematical calculations based on historic price and/or volume information that aims to show probable financial market direction. Technical indicators are fundamental part technical analysis and are typically plotted as a chart pattern to try and predict the market trend. Indicators generally overlay on price chart data to indicate where the price is going, or whether the price is in an "overbought" condition or an "oversold" condition.
Many technical indicators have been developed and new variants continue to be developed by traders with the aim of getting better results. New Indicators are often backtested on historic price and volume data to see how effective they would have been to predict future events.