When it comes to indicators, there are three classes: momentum indicators, trend-following indicators and volatility indicators. Knowing which one belongs to which category, and how to combine them in a meaningful way can help you make much better trading decisions. On the other hand, combining indicators in a wrong way can lead to a lot of confusion, wrong price interpretation and, subsequently, to wrong trading decisions.
Indicator redundancy – seeing the same things on different indicators
Indicator redundancy means that a trader uses multiple indicators which show the same information; indicator redundancy exists if a trader chooses two or more indicators from the same category.
The screenshot below shows a chart with 3 momentum indicators (MACD, RSI and the Stochastic). Essentially, all 3 indicators provide the same information because they examine momentum in price behavior; you can see that all indicators rise and fall simultaneously, flip together and also are flat during no-momentum periods (red boxes).
The next screenshot shows a chart with 2 trend indicators (the ADX and the Bollinger Bands). Again, the purpose of both indicators is the same – identifying trend strength. You can see that during a trend, the Bollinger Bands move down and price moves close to the outer Bands. At the same time, the ADX is high and rising. During a range, the Bollinger Bands narrow and move sideways and price just hovers around the center. The ADX is flat or going down during ranges.