Identify key differences between Funnel and Event Segmentation charts.

When you calculate conversion for a funnel in which users can complete the steps more than once, Amplitude buckets each user based on the values tied to the **first** occurrence of each event.

Understanding these implications is vital to drawing accurate conclusions from your analyses.

## First-touch attribution scenarios

Assume you have a funnel that tracks registrations (`complete registration`) **broken down by** the landing page each user sees (`view landing page`). If you **hold constant** by `session_id`, users must complete **both** steps of the conversion process in the **same session** for Amplitude to count them as converted.

### Scenario 1: Funnels using both _Hold property constant_ and _group conversions by_

When a funnel analysis uses both the hold constant and broken down by functions, Amplitude bases conversion on the **earliest entry within the session**.

Consider the following events and conversion results as examples:

| **Events**                                                                                                                  | **Conversion**                                                                                                                                                                                                                                                                   |
| --------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| A user sees Landing Page A and completes registration within the **same** session.                                          | The session counts as **converted**, and Amplitude attributes the conversion to Landing Page A.                                                                                                                                                                                  |
| A user sees Landing Page A, then Landing Page B in the **same** session, but converts only **after** seeing Landing Page B. | Since that user saw Landing Page A **first**, Amplitude attributes the conversion within the session to Landing Page A.                                                                                                                                                          |
| A user sees Landing Page A, then Landing Page B in **different** sessions.                                                  | That user **doesn't** convert in the session where they saw Landing Page A. But that same user **does** convert in the session where they saw Landing Page B. Amplitude counts the Landing Page A session as **not** converted, and the Landing Page B session as **converted**. |

{% callout type="note" %}
When you hold constant by session ID, your chart displays the **number of user sessions** that included a conversion, and **not** the number of users who converted.
{% /callout %}

### Scenario 2: Funnels using group conversions by, but not Hold property constant

When only the broken down by function applies, Amplitude bases conversion on the **earliest entry** within the lookback window.

Amplitude **groups** users by the first landing page they saw within the lookback window (how they entered the funnel). Amplitude considers them converted if they trigger the **final event** within the duration of the conversion window.

For example, consider the following events and related conversions:

| **Events**                                                                                                            | **Conversion**                                                                                                                            |
| --------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------- |
| A user sees Landing Page A and completes registration **within** the conversion window.                               | That user counts as **converted**, and Amplitude attributes the conversion to Landing Page A.                                             |
| A user sees Landing Page A, then Landing Page B, and completes registration **within** the window for Landing Page A. | That user counts as **converted**, and Amplitude attributes the conversion to Landing Page A, since they saw that one first.              |
| A user sees Landing Page A, then Landing Page B, but **doesn't convert**.                                             | That user counts as **not converted**. The events negatively affect Landing Page A's performance, but don't count against Landing Page B. |

{% callout type="note" %}
Amplitude calculates conversions broken down by a filter differently than a group-by. A group-by looks for the earliest and most complete conversion **first**, and then groups by the specified property value. A filter-by first accounts for the property you filter by **before** looking for a conversion.
{% /callout %}

## The logic of unique user counts in funnel analyses

When counting by **unique users**, the baseline conditions for conversion are:

- **A user must qualify for inclusion in the funnel**: Amplitude **can't filter the user out** through the user segmentation panel. Any filters set in the _Segment by_ module only apply at the time the user triggered the first funnel event.
- **A user must enter the funnel and complete all steps in the conversion window**: The user must enter the funnel and complete **all** steps within the stated **conversion window** to count as converted in the final funnel step. Otherwise, Amplitude counts the user based on how far they progressed through the funnel.

When Amplitude counts by uniques, it **only** counts the earliest and longest conversion for each unique user:

- **Longest**: In this context, longest means the **most complete** conversion—the completion of the most required steps within the funnel.

If Amplitude finds multiple conversions that meet the **longest** definition, it selects the first one and counts that as when conversion occurred.

- **Earliest**: Amplitude measures earliest using the **first converting sequence** chronologically, if more than one exists.

When you use the broken down by function, Amplitude continues to use the longest/earliest logic to bucket users according to the property that was present at their **point of funnel entry**.

If you use _Hold constant by_ in your analysis, Amplitude looks for the longest/earliest **converting sequence** within the same user session. When it does, the unit of measurement changes to unique user and session ID pairings.

When counting by **event totals**, the earliest/longest logic **doesn't apply**. Instead, Amplitude considers **all** conversion paths taken or attempted, rather than just the earliest/longest path per user. Amplitude then attributes the paths to the property for the event in the step it was broken down by.

## Funnels versus event segmentation

The Funnel and Event Segmentation charts provide different types of analyses, and can display different results. The following table highlights some of those differences:

| **Funnel**                                       | **Event Segmentation**                     |
| ------------------------------------------------ | ------------------------------------------ |
| Shows **steps** a user takes to gauge experience | Shows what **events** users are triggering |
| Filters only apply to the **first** step         | Filters apply to **every** event           |
| User **must execute step 1** to **enter funnel** | **No funnel** to enter                     |