About Levels and Factors

Use levels and factors to compare the effectiveness of different page elements in multiple combinations. During a multivariate test, visitors to the test page see a different variation of the elements and 'vote' with their clicks for the content they prefer.


A factor is a page element that can be tested. Common examples include headlines, hero shots, call-to-action buttons, copy, and imagery.


A level is a single variation of a page element. For example, a page element such as a call-to-action button may have four colors: green, orange, red, and blue. Each color represents a single level.


In the example below, there are three factors: a headline, a button, and a hero shot. The headline has two levels: green and orange. The button and the hero shot have four levels: green, orange, blue, and red.

factor and level matrix

Available Factors

When you create a multivariate test, test pages are created using a combination of page elements. Each combination is considered a single experiment within a test.

preview factors

Preview of Factors

Adding to Multivariate Projects

When you create a multivariate project you add a factor for each HTML element that you want to test. The factor name (Headline) and element ID (wt_headline) identifies the factor on the test page.

add factors

Adding a Factor to a Project

Adding to Multivariate Tests

When you create a multivariate test you select the number of levels to be tested for all factors. This is called a level set. To create a test that uses all the different levels in the above example—two headlines, four buttons, and four hero shots—you would select the level set 2 4 4.

Test duration increases with the number of factors and levels. The more combinations there are to display, the more time and site traffic you need for successful testing. When you create a project that has three or more factors, you choose a test methodology that determines the number of combinations to display: fractional factorial and full factorial.

Fractional Factorial Project

For a fractional factorial project, all the levels you select are included; however only a subset of the total number of page combinations is displayed to visitors. In this example, the selected 2 4 4 level set will create 16 page combinations or experiments.

choose level set for fractional test

Level Set for a Fractional Factorial Test

Full Factorial Project

For a full factorial project, a test page is created for every combination of page elements. In this example, the selected 2 4 4 level set will create 32 page combinations or experiments.

choose level set for full test

Level Set for a Full Factorial Test

After you select a level set, you add web content for each factor in the list.

assign levels and add content

assign levels and add content

Preview Factor Combinations

After you save the test, you can preview the factor combinations that will appear to your site visitors.

  1. Go to Laboratory and double-click the multivariate project.
  2. Select the test and click Preview.
  3. Select the project page or enter the URL for the page you want to preview.