# Interest shown

Learn how to check if a user has shown interest in a specific topic.

This expression checks if a user has shown interest in one or more topics based on [Interest shown](/reference/event/types/engagement/interest-shown) events.

> **Tracking required**
>
> Make sure your app is tracking the [Interest shown](/reference/event/types/engagement/interest-shown) 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 shown interest in /*<interests>*/
```

You can optionally include the article for better readability:

```cql
user has shown an interest in /*<interests>*/
```

The negation of the expression can be expressed as:

```cql
user has not shown interest in /*<interests>*/
```

You can refine the expression with quantifiers and time windows:

```cql
user has shown interest in /*<interests>*/ /*<quantifier>*/ /*<window>*/
```

## Parameters

These are the supported parameters:

- `interests`: `string | Array<string>`

  The specific topic(s) of interest to check for.

  For example, "ab testing", "analytics", "data science", etc.

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

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

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

  The time window during which the event must have occurred.

## Event properties

This event does not have additional properties.

## Examples

You can check whether a user has shown interest in a specific topic:

```cql
user has shown interest in "personalization"
```

Or check if they have not shown interest in that topic:

```cql
user has not shown interest in "personalization"
```

You can also check if the user is interested in at least one of the specified topics:

```cql
user has shown interest in ["personalization", "analytics", "data science"]
```

Or check whether the user showed interest in a topic at least twice:

```cql
user has shown interest in "personalization" at least 2 times
```

You can even filter by time, such as checking if the interest was recorded yesterday:

```cql
user has shown interest in "personalization" yesterday
```

Combine counts and time windows in one expression:

```cql
user has shown interest in "personalization" exactly 2 times last week
```

> **Scale plan**
>
> This feature is available only to accounts on the Scale plan. See the [pricing page](https://croct.com/pricing) for more information.

## Explore

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