> ## Documentation Index
> Fetch the complete documentation index at: https://docs.poly.ai/llms.txt
> Use this file to discover all available pages before exploring further.
## Submitting Feedback
If you encounter incorrect, outdated, or confusing documentation on this page, submit feedback:
POST https://docs.poly.ai/feedback
```json
{
"path": "/flows/asr-biasing",
"feedback": "Description of the issue"
}
```
Only submit feedback when you have something specific and actionable to report.
# ASR biasing
> Configure flow steps to improve speech recognition accuracy for structured inputs like codes and names.
**This page covers flow-level ASR configuration.** For dynamic ASR biasing from Python functions, see [`conv.set_asr_biasing()`](/tools/classes/conv-object). Setting up ASR biasing in the flow editor does not require code.
Automatic Speech Recognition (ASR) biasing helps the agent better understand expected types of user input in each step. It's especially useful for improving recognition of:
* Alphanumeric codes
* Names and name spellings
* Dates, times, and party sizes
* Addresses and yes/no responses
You can configure ASR biasing on any **flow step** to boost transcription accuracy. It will nudge transcription toward expected patterns, like confirmation codes or personal names.
## Where it appears
In the **step editor**, you'll see an **ASR biasing** panel on the right-hand side when editing a step prompt.
Options include:
* **Alphanumeric** – for booking references or confirmation codes.
* **Name** – for full personal names (first name, last name, or both).
* **Name spelling** – for phonetically spelled names (e.g., "A for apple").
* **Numeric** – for ages or short numbers.
* **Party size** – for group bookings.
* **Precise date** – for specific calendar dates.
* **Relative date** – for flexible time references (e.g., "next Tuesday", "in two weeks").
* **Single number** – for one-digit responses like menu selection.
* **Time** – for spoken times (e.g., "half past eight").
* **Yes/No** – for confirmation-style responses.
* **Address** – for location names, postcodes, or street numbers.
Custom keyword fields can also be added to bias transcription toward domain-specific vocabulary.
You can distinguish steps with ASR biasing already applied using the ear icon.
## When to use it
Enable ASR biasing when:
* Users are likely to say a structured input like a booking code or date.
* You're seeing frequent transcription errors.
* The agent is making incorrect guesses from unclear audio.
## Example in a flow
In the [flow taken from the example page](./example#e-asr-biasing), the agent is collecting a confirmation code. Because users often say mixed letters and numbers, we toggle **Alphanumeric** biasing.
This increases the likelihood that phrases like *"X9C7G2"* are heard and transcribed accurately.
## Best practices
* Match ASR bias to the input type, not the prompt phrasing.
* Combine biasing with [few-shot prompting](./few-shot-prompting) if needed.
* Always test key steps with real voice input.