Media Randomization

Understanding Steps

To understand how randomization works in EyesDecide, you should read about media flow steps first.

Since you can use the same media item in many steps, randomization is really about picking the next step in response to an event.

 A Quick Guide to Media Flow Randomization

Under ‘Studies’ > ‘Media Flow’:

Click the edit buttonscreen-shot-2016-12-06-at-03-49-24-pm

This pops-up the Workflow editor which has the option to determine whether a media item is a start step or not i.e. Do you want this media item to be displayed at random?

Select ‘YES. THIS IS A START STEP’ and save your changes.


Repeat this step for any other media you wish to be presented randomly and you’ll see this now reflected as a star next to each item indicating that is is a randomized start step.



Detailed Guide for Randomization Events

There are 3 events that cause randomization:

  • Viewer starts the session (a random start step is picked)
  • Viewer clicks on a media item
  • Media step timer elapses

When the session starts, viewers will be assigned to one of the “start steps” (marked with a star and sorted to the top of the list of steps). This immediately allows you to randomize viewers to one of several groups.

When you edit a step, the “timing & events” tab allows you to define the set of next steps for “on media click” and “on media timer” events. Both sets are separate – you can have different sets for both events, or only react to one event.

During viewing, the system will pick random next steps from these lists when the event occurs.


Show same media in different order

One common requirement is to display media in all possible orderings to remove the ordering bias from the results.

For example, if you have two media items A and B, you will want to display:

  • A then B
  • B then A

To do this, you would need 4 steps:

  • A1*, B2
  • B1*, A2

Steps A1 and A2 show media A. Steps B1 and B2 show media B. A1 and B1 are “start” steps, so half the viewers will see B1 and half the viewers will see A1.

You can link A1 to B2 and B1 to A2 either on a timer or a click event. No randomization should be used.

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