> For the complete documentation index, see [llms.txt](https://docs.sentiance.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sentiance.com/sdk/appendix/driving-score-validity.md).

# Driving Score Validity

### Score range

Driving Scores are represented on a scale from **0 to 1**. A higher score indicates safer driving behavior. 

In some situations the score cannot be determined and the result will be of a null value: `null` / `nil` depending on the platform.

### Minimum trip requirements

As a general guideline, a trip should be at least **2 km** long and last at least **3 minutes**, and the user's geofence must be breached for active data collection can begin. 

Scores are calculated once the transport has been completed, based on the [**driving events**](/getting-started/features-catalog/driving-insights.md#driving-events) detected during the trip.

If the trip is too short in duration, and/or the sensor or location data is missing or unreliable, the scores cannot be calculated. In that case, they'll be indicated with `null` / `nil`.

### Score is null or nil

A score of `null` or `nil` means the SDK was **unable to compute** the score for that trip.

This typically happens when:

* **The trip was too short** in duration or distance to collect enough data for a reliable score.
* **The location or sensor data was poor quality**, for example because of a weak GPS signal or excessive noise in the sensor data.

{% hint style="success" %}
**Why are scores not calculated when data is unreliable, instead of returning a score anyway?**

The SDK is built to only return a score when it can trust the data behind it. If a trip has too little or too poor-quality data, calculating a score anyway could produce a misleading result. The SDK returns `null`/`nil` to clearly signal "no reliable score available" instead of a guess.\
\
**The result:** every score you do receive can be trusted as an accurate reflection of real driving behavior.
{% endhint %}

#### Summary

<table><thead><tr><th width="128.5703125">Value</th><th>Meaning</th></tr></thead><tbody><tr><td><code>0 - 1</code></td><td>Valid score, with 0 indicating least safe driving detected and 1 being the highest.</td></tr><tr><td><code>null</code> / <code>nil</code></td><td><p>Score could not be computed due to</p><ul><li>Trip too short in duration</li><li>missing/unreliable sensor or location data</li></ul></td></tr></tbody></table>