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

# CustomMetric

> Custom metric for monitoring business-specific and domain-specific KPIs.

Custom metric for monitoring business-specific and domain-specific KPIs.

CustomMetric enables creation of user-defined metrics that calculate specific
values from model data using SQL-like expressions. Custom metrics extend
Fiddler's built-in monitoring capabilities to support business requirements,
domain-specific quality measures, and complex performance indicators.

## Example

```python theme={null}
# Business conversion rate metric
conversion_rate = CustomMetric(
    name="weekly_conversion_rate",
    model_id=model.id,
    definition="sum(if(prediction_score > 0.7 and converted == 1, 1, 0)) / sum(if(prediction_score > 0.7, 1, 0))",
    description="Conversion rate for high-confidence predictions"
).create()

# Data quality metric
missing_rate = CustomMetric(
    name="feature_missing_rate",
    model_id=model.id,
    definition="sum(if(is_null(income), 1, 0)) / count(income)",
    description="Percentage of records with missing income values"
).create()

# Fairness metric
fairness_metric = CustomMetric(
    name="demographic_parity",
    model_id=model.id,
    definition="abs((sum(if(gender == 'Male', predicted_churn, 0)) / sum(if(gender == 'Male', 1, 0))) - (sum(if(gender == 'Female', predicted_churn, 0)) / sum(if(gender == 'Female', 1, 0))))",
    description="Demographic parity difference between gender groups"
).create()

# Use in alert rule
alert_rule = AlertRule(
    name="conversion_rate_alert",
    model_id=model.id,
    metric_id=conversion_rate.id,
    priority=Priority.HIGH,
    compare_to=CompareTo.TIME_PERIOD,
    condition=AlertCondition.LESSER,
    bin_size=BinSize.DAY,
    critical_threshold=0.15,  # Alert if conversion drops below 15%
    compare_bin_delta=7
).create()
```

<Info>
  Custom metrics are calculated during data ingestion and monitoring cycles.
  Complex expressions may impact performance, so optimize for efficiency.
  Test expressions thoroughly before using in production alert rules.
</Info>

## create()

Create a new CustomMetric on the Fiddler platform.

Registers this CustomMetric with the Fiddler platform. The expression
must have a name, model\_id, and definition specified before calling create().

### Returns

<ResponseField type="CustomMetric">
  The same CustomMetric instance with updated server-side attributes
  (id, created\_at, etc.).
</ResponseField>

### Raises

* **ApiError** – If there's an error communicating with the Fiddler API.
* **Conflict** – If a CustomMetric with the same name already exists for this model.

## delete()

Delete this CustomMetric from the Fiddler platform.

Permanently removes the CustomMetric. This action cannot be undone.
Any alert rules or monitors using this CustomMetric must be deleted first.

### Raises

* **NotFound** – If the CustomMetric no longer exists.
* **ApiError** – If there's an error communicating with the Fiddler API.
* **Conflict** – If the CustomMetric is still being used by alert rules or monitors.

## *classmethod* from\_name()

Retrieve a CustomMetric by name and model.

Fetches a CustomMetric from the Fiddler platform using its name
and associated model ID.

### Parameters

<ParamField path="name" type="str" required={true}>
  The name of the CustomMetric to retrieve.
</ParamField>

<ParamField path="model_id" type="UUID | str" required={true}>
  UUID or string identifier of the associated Model.
</ParamField>

### Returns

<ResponseField type="CustomMetric">
  The CustomMetric instance for the provided parameters.
</ResponseField>

### Raises

* **NotFound** – If no CustomMetric exists with the specified name and model.
* **ApiError** – If there's an error communicating with the Fiddler API.

## *classmethod* get()

Retrieve a CustomMetric by its unique identifier.

Fetches a CustomMetric from the Fiddler platform using its UUID.

### Parameters

<ParamField path="id_" type="UUID | str" required={true}>
  The unique identifier (UUID) of the CustomMetric to retrieve.
  Can be provided as a UUID object or string representation.
</ParamField>

### Returns

<ResponseField type="CustomMetric">
  The CustomMetric instance with all its configuration and metadata.
</ResponseField>

### Raises

* **NotFound** – If no CustomMetric exists with the specified ID.
* **ApiError** – If there's an error communicating with the Fiddler API.

## *classmethod* get\_organization\_id()

Get the organization UUID from the global connection.

### Returns

<ResponseField type="UUID">
  Unique identifier of the organization associated with the current connection.
</ResponseField>

## *classmethod* get\_organization\_name()

Get the organization name from the global connection.

### Returns

<ResponseField type="str">
  Name of the organization associated with the current connection.
</ResponseField>

## *classmethod* list()

List all CustomMetric instances for a model.

Retrieves all CustomMetric instances associated with a specific model.

### Parameters

<ParamField path="model_id" type="UUID | str" required={true}>
  UUID or string identifier of the Model.
</ParamField>

### Yields

CustomMetric instances for each CustomMetric in the model.

### Raises

**ApiError** – If there's an error communicating with the Fiddler API.

### Returns

`Iterator[CustomMetric]`

## **init**()

Construct a custom metric instance.