# Lead generated

Learn how to check if a user has become a lead.

This expression verifies whether the user has become a lead based on [Lead generated](/reference/event/types/engagement/lead-generated) events.

> **Tracking required**
>
> Make sure your app is tracking the [Lead generated](/reference/event/types/engagement/lead-generated) event before using this expression. Without this event, the expression will always evaluate to false.

## Syntax

The basic syntax for this expression is:

```cql
user has become a lead
```

The negation of the expression can be expressed as:

```cql
user has not become a lead
```

You can refine the expression with criteria, quantifiers, and time windows:

```cql
user has become a lead /*<criteria>*/ /*<quantifier>*/ /*<window>*/
```

## Parameters

These are the supported parameters:

- `criteria`: [`Criteria`](/reference/cql/expressions/events/criteria/overview) (optional)

  Additional [filtering criteria](#event-properties) for the link opened event.

- `quantifier`: [`Quantifier`](/reference/cql/expressions/events/quantifier) (optional)

  A quantifier to specify how many times the sign up must have occurred.

- `window`: [`TimeWindow`](/reference/cql/expressions/events/time-window) (optional)

  The time window during which the sign up must have occurred.

## Event properties

- `id`: `string|null`

  The ID of the lead.

## Examples

You can check whether a user has become a lead:

```cql
user has become a lead
```

Or check if they have not:

```cql
user has not become a lead
```

You can also add criteria, such as specifying an ID:

```cql
user has not become a lead with id "123"
```

You can also check how many times a user has become a lead:

```cql
user has become a lead at least 2 times
```

You can even filter by time, such as checking if a sign‑up happened yesterday:

```cql
user has become a lead yesterday
```

Combine criteria, quantifiers and time-based conditions:

```cql
user has become a lead with id "123" at least 2 times this month
```

## Explore

- [Audiences](/explanation/audience): Understand how to delivery content to specific groups of users.
- [Event tracking](/reference/event/types/engagement/lead-generated): Learn how to track this event.