> ## Documentation Index
> Fetch the complete documentation index at: https://docs.startree.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# PERCENTAGE_CHANGE

Compares the current timeseries to a baseline. If the current value is not in `[baseline - percentage * baseline, baseline + percentage * baseline]`, detects an anomaly.

## Inputs

`"targetProperty": "current"`: The data on which to perform detection.

`"targetProperty": "baseline"`: The data to use as a baseline.

The inputs should have the same size.

## Parameters

| name                         | description                                                                                                                          | default value |
| ---------------------------- | ------------------------------------------------------------------------------------------------------------------------------------ | ------------- |
| `component.percentageChange` | The percentage threshold. If the percentage change is above this threshold, detect an anomaly.    In ratio. Eg 0.1 means 10 percent. | `Inf`         |
| `component.pattern`          | Detect as an anomaly if the metric drop, rise or both directions. `UP`, `DOWN`, `UP_OR_DOWN`.                                        | `UP_OR_DOWN`  |

## Example

```json theme={null}
{
    "name": "root",
    "type": "AnomalyDetector",
    "params": {
    "type": "PERCENTAGE_CHANGE",
    "component.percentageChange": "0.2",   # 20% threshold 
    "component.pattern": "UP",             # only detect change up       
      ...  # shared parameters
    }, 
  "inputs": [
    {    # baseline data
      "targetProperty": "baseline",               
      "sourcePlanNode": "baselineDataFetcher",
      "sourceProperty": "baselineOutput"
    },
    {    # current data
      "targetProperty": "current",                
      "sourcePlanNode": "currentDataFetcher",
      "sourceProperty": "currentOutput"
    }
  ]
}
```