GA4 Item Funnel

💎Premium Feature

This module is available exclusively for Premium users.

The ga4_item_funnel module processes GA4 e-commerce data to create datasets focused on item-level performance throughout the buying journey.

It transforms nested event and item data into structured funnels and attribution-ready outputs, showing how users interact with individual products across steps such as view_item_list, select_item, view_item, add_to_cart, begin_checkout, and purchase.

Functional Overview and Business Value

Product performance optimization: Identify products that are frequently viewed but rarely added to cart versus products that convert strongly once discovered.
Funnel bottleneck detection: Pinpoint where user drop-off happens for specific product lines, brands, or categories.
Item-list attribution: Measure which lists (for example Search Results, Related Products, Summer Sale) drive engagement and sales.
Customizable insights: Tailor reporting with optional item and session drilldowns.

Attribution Models

Item-list attribution is based on item list impressions and supports:

First: Credits the first list where an item was seen in the session.
Last: Credits the most recent list where an item was seen in the session.

This enables attribution even when later events (like purchase) do not include list parameters.

Output Table Descriptions

The module produces three output tables for different analysis needs.

`ga4_item_funnel_sessions`

Description: Granular, intermediate-style reporting table.
Granularity: 1 row per item per session.
Functionality: Aggregates e-commerce item events at session + item level and includes base session attributes plus list attribution arrays.

`ga4_item_funnel_report`

Description: Aggregated daily funnel reporting table.
Granularity: Grouped by session_date, enabled item dimensions, and enabled drilldowns.
Functionality: Primary BI table with event/session/user funnel metrics and purchase revenue/quantity.

`ga4_item_list_attribution_report`

Description: Aggregated reporting table focused on item-list performance.
Granularity: Grouped by session_date and configured item-list dimensions.
Functionality: Provides first-touch and last-touch list attribution metrics for downstream engagement and sales.

Technical Configuration (`config.json`)

The module uses a single configuration file: includes/custom/modules/ga4_item_funnel/config.json

Example:

{
    "version": 1,
    "enabled": true,
    "dependencies": ["ga4"],
    "drilldowns": {
        "channel_group": true,
        "device_category": true,
        "is_new_session": true
    },
    "listAttribution": {
        "saveListInformation": true,
        "dimsToStore": ["item_list_name", "item_list_id", "item_list_index"],
        "pickDimsFromTheseEvents": ["view_item_list", "select_item", "view_item"]
    },
    "itemDrilldowns": {
        "item_id": true,
        "item_name": true,
        "item_brand": false,
        "item_variant": false,
        "item_category": true,
        "item_category2": false,
        "item_category3": false,
        "item_category4": false,
        "item_category5": false,
        "affiliation": false
    },
    "itemParamsCustom": [
        { "name": "item_params_custom.item_stocklevel", "renameTo": "stock" }
    ],
    "sessionDimensions": [
        { "name": "session_params_custom.page_language", "renameTo": "language" },
        { "name": "geo.country" }
    ]
}

Configuration Options

Essential Settings

Setting	Description	Example
`enabled`	Enable/disable the module	`true` or `false`
`version`	Configuration version (must remain `1`)	`1`
`dependencies`	Required module dependencies	`["ga4"]`

Session-Level Drilldowns

Configure which session dimensions to include:

"drilldowns": {
    "channel_group": true,
    "device_category": false,
    "is_new_session": false
}

Available Options:

channel_group: Adds last_non_direct_traffic_source.default_channel_grouping column
device_category: Adds device segmentation (desktop, mobile, tablet, smart tv)
is_new_session: Enables new vs. returning user analysis using ga_session_number = 1 logic

List Attribution Settings

Configure extraction and stateful tracking of item-list properties:

"listAttribution": {
    "saveListInformation": true,
    "dimsToStore": ["item_list_name", "item_list_id", "item_list_index"],
    "pickDimsFromTheseEvents": ["view_item_list", "select_item", "view_item"]
}

saveListInformation (boolean): Enables list tracking and attribution logic.
dimsToStore (array of strings): List dimensions to persist (item_list_name, item_list_id, item_list_index).
pickDimsFromTheseEvents (array of strings): Events scanned to capture list metadata for later funnel events.

Item Dimension Drilldowns

Toggle standard item dimensions on/off:

"itemDrilldowns": {
    "item_id": true,
    "item_name": true,
    "item_brand": true,
    "item_variant": true,
    "item_category": true,
    "item_category2": true,
    "item_category3": true,
    "item_category4": true,
    "item_category5": true,
    "affiliation": true
}

Consistency Matters

Disable item dimensions that aren't filled consistently across all e-commerce events, as they can "break" funnel analysis when drilling down. For example, if view_item_list has no item_variant but add_to_cart does, consider disabling item_variant.

Custom Item Parameters

Include custom item parameters from your configuration:

"itemParamsCustom": [
    { "name": "item_params_custom.item_stocklevel", "renameTo": "stock" }
]

Parameter Names

Use fully qualified source fields that exist in your available item parameters and map them with renameTo when needed.

Example:

[
    { name: "item_params_custom.item_stocklevel", renameTo: "stock" }
]

Additional Session Dimensions

Add any column from the ga4_sessions table:

"sessionDimensions": [
    { "name": "session_params_custom.page_language", "renameTo": "language" },
    { "name": "geo.country" }
]

name: Valid column name from ga4_sessions table
renameTo: Optional renamed column in output (auto-sanitized if omitted)

Table Structures

`ga4_item_funnel_sessions`

Granularity: 1 row per item per session with aggregate metrics

Column	Description
`session_date`	Date of the session (partitioning column) - based on start date of the session
`session_start_timestamp_utc`	UTC timestamp when the session started
`session_start_timestamp_local`	Local datetime when the session started (converted using LOCAL_TIMEZONE variable)
`is_final`	Indicates if the data is final or subject to change (based on 72h window)
`session_id`	Unique identifier for the session - contains only non-NULL values (cluster column)
`ga_session_number`	Google Analytics session number for the user
`user_pseudo_id`	Pseudonymous identifier for the user
`user_id`	Unique identifier for the user - last non-null value of the session
`property_id`	Google Analytics property ID
`platform`	The data stream platform (Web, IOS or Android) from which the event originated
Item Details
`item.item_id`	Unique identifier for the item
`item.item_name`	Name of the item
`item.item_brand`	Brand of the item
`item.item_variant`	Variant of the item (e.g., size, color)
`item.item_category`	Primary category of the item
`item.item_category2`	Secondary category of the item
`item.item_category3`	Tertiary category of the item
`item.item_category4`	Fourth-level category of the item
`item.item_category5`	Fifth-level category of the item
`item.price_in_usd`	Item price converted to USD
`item.price`	Item price in local currency
`item.quantity`	Quantity of the item in the event
`item.item_revenue_in_usd`	Revenue from this item converted to USD
`item.item_revenue`	Revenue from this item in local currency
`item.item_refund_in_usd`	Refund amount for this item converted to USD
`item.item_refund`	Refund amount for this item in local currency
`item.coupon`	Coupon code applied to this item
`item.affiliation`	Affiliation or partner associated with the item
`item.location_id`	Physical location identifier where the item was sold
`item.item_list_id`	Identifier for the list where the item appeared
`item.item_list_name`	Name of the list where the item appeared
`item.item_list_index`	Position of the item in the list
`item.promotion_id`	Identifier for the promotion applied to the item
`item.promotion_name`	Name of the promotion applied to the item
`item.creative_name`	Name of the creative/ad that promoted the item
`item.creative_slot`	Slot position of the creative/ad
E-commerce Event Totals
`item_totals.add_payment_info`	Number of times payment info was added for this item in the session
`item_totals.add_shipping_info`	Number of times shipping info was added for this item in the session
`item_totals.add_to_cart`	Number of times this item was added to cart in the session
`item_totals.add_to_wishlist`	Number of times this item was added to wishlist in the session
`item_totals.begin_checkout`	Number of times checkout was initiated with this item in the session
`item_totals.purchase`	Number of times this item was purchased in the session
`item_totals.refund`	Number of times this item was refunded in the session
`item_totals.remove_from_cart`	Number of times this item was removed from cart in the session
`item_totals.select_item`	Number of times this item was selected in the session
`item_totals.select_promotion`	Number of times a promotion for this item was selected in the session
`item_totals.view_cart`	Number of times cart containing this item was viewed in the session
`item_totals.view_item`	Number of times this item was viewed in the session
`item_totals.view_item_list`	Number of times a list containing this item was viewed in the session
`item_totals.purchase_quantity`	Total quantity of this item purchased in the session
`item_totals.item_revenue`	Total revenue generated by this item in the session

`ga4_item_funnel_report`

Granularity: Daily aggregates by item and configured dimensions

Column	Description
`session_date`	Date of the session used for aggregation (partitioning column for performance optimization)
`property_id`	Google Analytics property ID
`platform`	The data stream platform (Web, IOS or Android) from which the events originated
`is_final`	Indicates if the data is final or subject to change (based on 72h window)
Dynamic Item Dimensions (conditionally included)
`item.item_id`	Unique identifier for the item (included if `itemDrilldowns.item_id = true`)
`item.item_name`	Name of the item (included if `itemDrilldowns.item_name = true`)
`item.item_brand`	Brand of the item (included if `itemDrilldowns.item_brand = true`)
`item.item_variant`	Variant of the item (included if `itemDrilldowns.item_variant = true`)
`item.item_category`	Primary category of the item (included if `itemDrilldowns.item_category = true`)
`item.item_category2`	Secondary category of the item (included if `itemDrilldowns.item_category2 = true`)
`item.item_category3`	Tertiary category of the item (included if `itemDrilldowns.item_category3 = true`)
`item.item_category4`	Fourth-level category of the item (included if `itemDrilldowns.item_category4 = true`)
`item.item_category5`	Fifth-level category of the item (included if `itemDrilldowns.item_category5 = true`)
`item.affiliation`	Affiliation or partner associated with the item (included if `itemDrilldowns.affiliation = true`)
`item.{custom_param_name}`	Custom item parameters as specified in `itemParamsCustom` array - field names match the configured parameter names
Session-Level Drilldowns (conditionally included)
`default_channel_grouping`	Default channel grouping for traffic attribution (included if `drilldowns.channel_group = true`)
`device_category`	Device category (Desktop, Mobile, Tablet, Smart TV) (included if `drilldowns.device_category = true`)
`is_new_session`	Boolean indicating if this was the user's first session (included if `drilldowns.is_new_session = true`)
Custom Session Dimensions (dynamically added)
`{custom_dimension_name}`	Additional dimensions from `ga4_sessions` table as specified in `sessionDimensions` configuration array - column names determined by `renameTo` value or auto-sanitized from original field name
Comprehensive Funnel Metrics
`item_totals.events.{event_name}`	Total count of each e-commerce event type for this item (e.g., `add_to_cart`, `purchase`, `view_item`)
`item_totals.sessions.{event_name}`	Count of unique sessions where each e-commerce event type occurred for this item
`item_totals.users.{event_name}`	Count of unique users who performed each e-commerce event type for this item
`item_totals.purchase_quantity`	Total quantity of this item purchased across all purchase events
`item_totals.item_revenue`	Total revenue generated by this item across all purchase events

Dynamic Schema

ga4_item_funnel_report adapts its schema based on configuration:

Item dimensions: Only enabled itemDrilldowns appear in the item struct
Custom item parameters: Fields from itemParamsCustom array are dynamically added
Session drilldowns: Only enabled drilldowns create additional columns
Custom session dimensions: Additional columns based on sessionDimensions configuration
Event metrics: All standard e-commerce events are tracked (13 event types total)

`ga4_item_list_attribution_report`

Granularity: Daily aggregates by item-list dimensions and configured drilldowns

Column	Description
`session_date`	Session date used for aggregation
`property_id`	Google Analytics property ID
`platform`	Data stream platform (Web, IOS, Android)
`is_final`	Indicates if data is final (72h window logic)
`item_list.item_list_name`	Item list name (if enabled in `listAttribution.dimsToStore`)
`item_list.item_list_id`	Item list ID (if enabled in `listAttribution.dimsToStore`)
`item_list.item_list_index`	Item list index (if enabled in `listAttribution.dimsToStore`)
`attribution_first.events.{event_name}`	Event counts attributed to first list impression of the item in-session
`attribution_last.events.{event_name}`	Event counts attributed to most recent list impression of the item in-session
`attribution_first.item_revenue`	Revenue attributed with first-touch list model
`attribution_last.item_revenue`	Revenue attributed with last-touch list model

Looker Studio Template + Calculation Examples

tip

We created a free-to-use Looker Studio template that was specifically designed to work with the GA4Dataform modules. Feel free to copy it and adapt it to your needs! You can find it here.

When connecting ga4_item_funnel_report to your BI tool, here are useful calculated metrics:

Event-Based Metrics

sum(item_totals.events.add_to_cart): Total add-to-cart events for item
sum(item_totals.events.purchase): Total purchase events for item

Session-Based Metrics

sum(item_totals.sessions.purchase): Sessions where item was purchased
sum(item_totals.sessions.view_item): Sessions where item was viewed

User-Based Conversion Rates

sum(item_totals.users.purchase) / sum(item_totals.users.view_item): User-based purchase-to-detail rate
sum(item_totals.users.add_to_cart) / sum(item_totals.users.view_item): User-based view-to-cart rate

Revenue Metrics

sum(item_totals.item_revenue): Total item revenue
sum(item_totals.purchase_quantity): Total units sold
sum(item_totals.item_revenue) / sum(item_totals.purchase_quantity): Average selling price

Common Use Cases

Product Performance Analysis: Identify top and bottom-performing items across the funnel
Category Optimization: Compare performance across product categories
List Attribution Analysis: Compare first-touch vs. last-touch list impact on conversions
Inventory Planning: Use purchase quantities and revenue data for demand forecasting
Personalization Insights: Analyze item performance by user segments
A/B Testing: Compare item performance across different user experiences

Functional Overview and Business Value​

Attribution Models​

Output Table Descriptions​

ga4_item_funnel_sessions​

ga4_item_funnel_report​

ga4_item_list_attribution_report​

Technical Configuration (config.json)​

Configuration Options​

Essential Settings​

Session-Level Drilldowns​

List Attribution Settings​

Item Dimension Drilldowns​

Custom Item Parameters​

Additional Session Dimensions​

Table Structures​

ga4_item_funnel_sessions​

ga4_item_funnel_report​

ga4_item_list_attribution_report​

Looker Studio Template + Calculation Examples​

Event-Based Metrics​

Session-Based Metrics​

User-Based Conversion Rates​

Revenue Metrics​

Common Use Cases​

Functional Overview and Business Value

Attribution Models

Output Table Descriptions

`ga4_item_funnel_sessions`

`ga4_item_funnel_report`

`ga4_item_list_attribution_report`

Technical Configuration (`config.json`)

Configuration Options

Essential Settings

Session-Level Drilldowns

List Attribution Settings

Item Dimension Drilldowns

Custom Item Parameters

Additional Session Dimensions

Table Structures

`ga4_item_funnel_sessions`

`ga4_item_funnel_report`

`ga4_item_list_attribution_report`

Looker Studio Template + Calculation Examples

Event-Based Metrics

Session-Based Metrics

User-Based Conversion Rates

Revenue Metrics

Common Use Cases