> For the complete documentation index, see [llms.txt](https://docs.origami.tech/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.origami.tech/reference/grid-language/indicators/kaufman-efficiency-indicator.md).

# Kaufman Efficiency Indicator

er() calculates the Kaufman Efficiency Ratio from candles to show how clean or noisy a trend is.

Learn how to use the Kaufman Efficiency Indicator in Origami Tech to measure trend efficiency and identify stable, low-noise market conditions.

## Kaufman Efficiency Indicator

`er(candles: List[[Candle]], period: int = 14, column: str = "close") -> List[Decimal]`