eVar (Merchandising)

This help page describes how merchandising eVars work as a dimension. For information on how to implement merchandising eVars, see eVar (merchandising variable) in the Implementation user guide.

A merchandising eVar works like a standard eVar, except that each product has its own copy of it. Persistence, allocation, and expiration all work the same way, but separately for each product. A standard eVar holds one persisted value per visitor that receives credit for every success event. A merchandising eVar holds one persisted value per product, and that value receives credit for that product’s success events:

Each product’s value can be set or changed only on hits that include that product. Once set, the value persists until it expires and receives credit only for that product’s success events. Changing product A’s value has no effect on product B.

Merchandising eVars work only with the products variable. A merchandising eVar value that is not bound to a product receives no credit. Success events on hits without products are attributed to "None" for every merchandising eVar.

Why use merchandising eVars

Keeping a separate value for each product matters when a single value shouldn’t receive credit for everything a visitor buys. A standard eVar works well for external campaigns or external search terms, where one value should receive credit for any success events that occur. For example, if a customer clicks a link in an email campaign to visit your website, all purchases made as a result should be credited to that campaign.

Internal search and category browsing are different, because a visitor often uses them to find several products, each in a different way. For example, a customer searches your site for "goggles", then adds a pair to their cart:

Before checkout, the customer searches for "winter coat", then adds a down jacket to their cart:

When the visitor completes this purchase, the internal search term "winter coat" receives credit for the entire order, including the goggles, because it’s the eVar’s most recent value (the default allocation of Most Recent (Last)). The search term "goggles" receives no credit, even though it led to part of the purchase:

How merchandising eVars solve this problem

If merchandising is enabled for the eVar in the previous example, the search term "goggles" is bound to the snow goggles, and the search term "winter coat" is bound to the down jacket. Merchandising eVars allocate revenue at the product level, so each term receives credit for the amount of revenue for the product to which the term is bound:

How binding and allocation work

Merchandising eVars rely on three concepts:

Each merchandising eVar uses one of two syntaxes, set in the Merchandising setting in report suite settings. The syntax determines how a value reaches a product:

Both syntaxes use the same binding, allocation, and expiration behavior described above. They differ in the following ways:

Product syntax

With product syntax, the eVar value is set on each product in the products variable. In the products string, the value after the last semicolon of a product is its merchandising eVar. See Implement using product syntax for the full syntax.

The value binds directly to that product on that hit. Binding events are not used. Later hits that include the product, such as a cart add or purchase, do not need to repeat the value. Because each product carries its own value, product syntax is the only option when products in the same hit need different values.

s.events = "purchase";
s.products = ";tshirt123;1;20;;eVar10=tshirt123-m-blue,;tshirt123;1;20;;eVar10=tshirt123-l-red";

The tradeoff is that product syntax requires the complete value string on each product whenever binding should occur. For product finding methods, which typically use several eVars at once, the string looks like this:

s.products = ";sandal123;;;;eVar2=sandals|eVar1=internal keyword search|eVar3=non-internal campaign|eVar4=non-browse|eVar5=non-cross-sell";

A finding method should receive credit only after the visitor interacts with a product, so this string is typically set on the product detail page or on a cart add, not on the search results page. To do so, developers must:

Conversion variable syntax avoids both requirements.

Conversion variable syntax

With conversion variable syntax, the value is set in the eVar itself:

s.eVar1 = "internal keyword search";

The eVar acts as a staging area. A value set in the eVar is held there until a binding event binds it to the products on a hit. Binding occurs in two stages:

If the eVar, the products variable, and a binding event are all set on the same hit, staging and binding happen simultaneously. The new value binds immediately to the products on that hit.

Setting the eVar alongside a product without a binding event does not bind the value to that product. A staged value receives no credit until it is bound to a product.

What binding events do

A binding event is the trigger that tells Adobe to bind the staged value to the products on the hit.

// Hit 1
s.eVar1 = "internal keyword search";
s.eVar2 = "sandals";

// Hit 2
s.products = ";sandal123";
s.events = "prodView";

Best practice: product finding methods

Most retail sites benefit from tracking the following product finding methods, each as a merchandising eVar:

When a visitor uses one method, set the other finding method eVars to a “non-” value. Otherwise, an unused method’s earlier value could receive credit for a product found through another method. For example, on the results page for an internal search for “sandals”:

s.eVar1 = "internal keyword search";
s.eVar2 = "sandals";
s.eVar3 = "non-internal campaign";
s.eVar4 = "non-browse";
s.eVar5 = "non-cross-sell";

With conversion variable syntax, developers can set only simple values, such as a search term in a prop, and logic in your implementation can fill in the merchandising eVars. Nothing needs to be passed between pages or built into the products string. The products variable is still required on the hits where binding occurs.

Adobe recommends the following settings for product finding method eVars:

See Conversion variables in the Admin guide for a description of each setting.

Instances on merchandising eVars

The default Instances metric is not recommended for use on merchandising variables.

Since most use cases for conversion variable syntax require the eVar and products variable on different hits, the default Instances metric is not realistic to use.

To count instances for each value sent with conversion variable syntax, apply the Last Touch attribution model to the Instances metric. Attribution models use the values sent on each hit, not staged values or product bindings. The lookback window does not matter, because Last Touch credits each value on the hit where it was sent, regardless of the eVar’s allocation setting.