Randomize Concepts in Your Strella Interview Guide

Reduce order bias when testing multiple concepts by assigning participants to exclusive variants or shuffling all variants into a different sequence.

When you test multiple concepts, images, or prototypes in a single study, the order in which participants encounter them can skew their feedback—people tend to rate things differently depending on what they’ve already seen. Randomization removes that bias by varying the sequence or assignment across participants automatically.

Two Types of Randomization

Exclusive

Each participant is assigned one variant at random and never sees the others. Use this for monadic testing when you want clean, uncontaminated reactions to a single concept.

Shuffle

Participants see all variants in a random order. Use this for sequential monadic testing when you need comparative data but want to neutralize order effects.

Monadic testing (Exclusive) gives you the purest single-concept reactions. Sequential monadic testing (Shuffle) lets participants compare concepts while still controlling for presentation order.

Setting Up Randomization

1. Click Add a step

   In the left-hand guide panel, scroll to the bottom and click Add a step.

2. Select Randomization

   From the element menu, click Randomization. A randomization block will appear in your guide.

3. Configure the randomization block

   Click the randomization block to open its settings in the right-hand panel. Set the following properties:

   • Label — An internal name to identify this randomization block (participants won’t see this).
   • Variant names — Name each variant (e.g., Concept A, Concept B, Concept C).
   • Add or remove variants — Use the controls to add more options or remove existing ones.
   • Distribution — Select Exclusive or Shuffle.
4. Add content to each variant

   Each variant defaults to a question. To add a different element type—such as an image—click the three dots beside the variant name, then click the + icon and select the element you want (e.g., Image).

5. Upload your concept content

   Click the Click to upload box in the right-hand panel to upload the image or file for that variant. Repeat for each variant.

Example: Testing Three Image Concepts

Here is how to set up a randomized image test for three visual concepts.

1. Add a Randomization block

   Click Add a step and select Randomization. Label the block Concept Test.

2. Name three variants

   Rename the default variants to Concept A, Concept B, and Concept C. Add a third variant if only two are shown by default.

3. Set distribution

   Choose Exclusive if each participant should see only one concept, or Shuffle if they should see all three in a random order.

4. Add an image to each variant

   For each variant, click the three dots beside the variant name → click the + sign → select Image → upload the concept image in the right-hand panel.

5. Add follow-up questions inside each variant

   After each image, add an open question such as: What is your initial reaction to this concept? This ensures the AI moderator captures qualitative feedback immediately after participants see each image.

You can randomize any media type—not just images. Follow the same steps to randomize Figma prototypes, videos, or embedded content across variants.