---
title: "Missing shared context: confirm the coverage gap"
description: "Define the context important events should share, then use the tracking plan and Observe to find where it's missing."
product: data
token_estimate: 1208
---
# Missing shared context: confirm the coverage gap

> For AI agents: a documentation index is available at [/docs/llms.txt](/docs/llms.txt). Append `.md` to any page URL for markdown, or send `Accept: text/markdown`.

Shared properties should appear on nearly every event. Examples include platform, app version, product area, tenant, and release channel. When some events or sources omit a shared property, you can't reliably break down analysis by that property. When you group by a missing event or user property, Amplitude places the affected events or users in the `(none)` bucket.

Your analysis requirements determine which properties count as shared context, so Data Assistant doesn't identify missing shared context. Define the shared-property standard, then compare the standard against your tracking plan and observed data. The audit requires no code, but closing coverage gaps usually requires an instrumentation change.

Run this audit when breakdowns by a key dimension look incomplete or as part of a taxonomy review. Use Amplitude's default SDK properties when they answer your analysis question. Add a custom shared property only for a specific analysis or governance need.

## Define the shared property set

1. List the analysis questions that need context across many events.
2. For each question, decide whether the context describes the person or an event occurrence. Use a user property for a persistent person-level attribute. Use an event property for context at the time of the action.
3. Remove fields that duplicate Amplitude's [default user properties](https://amplitude.com/docs/data/user-properties-and-events#user-properties).
4. Agree on the property name, type, allowed values, owner, and privacy classification.
5. Identify the events and sources that must send the property.

## Check coverage in Amplitude Data

1. Go to _Data > Properties_ and search for each approved property.
2. Open the property and review which events and sources use the property.
3. Create a [property group](https://amplitude.com/docs/data/property-updates-property-groups) when many planned events need the same event properties.
4. Mark each required event-property relationship in the tracking plan.
5. Open [Observe](https://amplitude.com/docs/data/validate-events) and review the `% Seen` indicator for each required property and source.
6. Record events where the property is absent, has the wrong type, or appears only on some sources.

> **Note:** The tracking plan doesn't populate values
>
> Adding a property or property group to the plan defines the expected schema. The tracking plan doesn't add the property to incoming events. Engineering has to update each affected source.

## How Amplitude can address missing shared properties

Amplitude can't add a property to historical events that never included the property. The tracking plan defines expectations rather than data. If existing raw properties already contain the value, a [derived property](https://amplitude.com/docs/data/derived-properties) can compute the value at query time. A derived property supports analysis but doesn't change the source payload or fill the ingestion gap for the original property.

> **Tip:** Ask Global Agent
>
> [Global Agent](https://amplitude.com/docs/amplitude-ai/global-agent-overview) can quantify the coverage gap. Try this prompt:
>
> "Build a chart of \[EVENT\] grouped by \[PROPERTY\] for the last 30 days and show the share of events with no value for \[PROPERTY\]."
>
> Review the generated chart and supporting data to measure the `(none)` bucket. Global Agent can't add the property to events that don't send the property.

## Send coverage gaps to your tracking owner

Closing shared-property coverage gaps requires a source change. Send your engineers the property contract and affected sources. Copy this template and fill in the brackets:

```text
We need shared property [NAME] ([user property / event property], type [TYPE],
allowed values [VALUES]) on [these events / all events] from [these sources]. In
Observe it's missing or partial on [SOURCES / EVENTS]. Send it
consistently, with the same name, type, and values across web, mobile, backend,
and any CDP mapping. It's blocking breakdowns by [DIMENSION].
```

## If you have no engineering resources

If a derived property can't meet the analysis need, meeting the need requires a source change. Contact these resources in order:

- Your Amplitude account team or Customer Success Manager.
- A partner or agency that manages your website or app analytics.
- Amplitude Support at [gethelp.amplitude.com](https://gethelp.amplitude.com) for product questions.

When you're ready to fix the missing sources, continue with the [engineering solution](https://amplitude.com/docs/data/data-assistant-user-solutions/shared-properties-engineering).