Add Least Filled Tags vs. Retain Least Filled Tags.

Least Filled Tags is a powerful and popular tool that allows you to distribute your respondents equally across each of your tags or concepts. This is perfect for Concept Testing or Ad Pre-Testing use cases. It’s simple to use once you see how it works below.

Least fill allocates respondents to the tags with the lowest count. E.g. if...

• tag 1 has n=331 respondents,
• tag 2 has n=333, and
• tag 3 has n=335,

...then the next respondent will get allocated to tag 1, which has the lowest count. There will be tiny variation (as some respondents might enter the survey at the same time), but they'll be tiny.  

In contrast, if you were to randomly allocate to each tag (e.g. using "sample" feature),

• tag 1 might have n=310 respondents,
• tag 2 might have n=360
• tag 3 might have n=330.

The average is n=333 respondents p/tag

But random allocation creates unacceptably large variation in tag distribution.

Least fill on the other hand, fixes the problem of big variation by guaranteeing almost perfect equality, allowing you to compare concepts fairly, without partiality or bias.

Add Least Filled Tags

Let's say you have 3 new drink concepts you want to test in your survey capturing n=1000 responses and you want...

• 1/3 to see drink 1: hibiscus rose
• 1/3 to see drink 2: lavender oolong and
• 1/3 to see drink 3: apple berry

...with tiny variation. The only way this can be done is with least fill logic.

To add least filled logic:

1. Click the logic editor at the question where you want to add least fill logic
2. Click Add Action Logic
3. In the 'If...' dropdown, input your condition, e.g. if respondent answered Q12
4. In the 'Then...' dropdown, pick 'add least filled tags'
5. In the 'Tags' dropdown, type in your drink tags in the 'Custom' field and press enter for each one

6. In the 'Set amount to least fill' dropdown, pick the number of tags you want to allocate to respondents, typically 1, but you can pick any number less than the total tags selected in the 'Tags' dropdown. E.g. above we have 3 drinks selected so you can allocate either 1/3 or 2/3 tags to respondents.

7. click Save & Close

Least Filled Tags is typically used in combination with Display Logic as you want to display questions or options depending on which Tag respondents were allocated. E.g. display Q13 if respondent has tags - D1: Hibiscus Rose

If we were to click "Show Logic" in our survey menu, our least fill logic & display logic might look like below:

• 1/3 will see Q13 for Hibiscus Rose,
• 1/3 will see Q14 for Lavender Oolong,
• 1/3 will see Q15 for Apple Berry.

See article: Add Display Logic.

Use 'add least filled tags' when respondents have none of the tags needed and you want to add them based on least fill.

Retail Least Filled Tags

Use 'retain least filled tags' when respondents have all of the tags needed, but you only want the respondent to retain a portion of the tags that they've qualified for and remove the rest of the tags.

Example: let's say at Q2: Brands Bought in P12m, there are 11 brands respondent can select, and they get tagged as that brand in the logic editor if they select it.

However, for the rest of the survey, you want respondents to answer questions for a maximum of 3 out of all 11 possible brands that they could be tagged as bought in P12m at Q2 based on whichever 3 tags have the lowest count and remove the rest of the tags.

E.g. if a respondent selected 6 brands at Q2 with the following tag counts...

1. Brand A with n=300
2. Brand B with n=180
3. Brand F with n=350
4. Brand L with n=250
5. Brand O with n=190
6. Brand W with n=200

...then you want this respondent to retain the Brand B, Brand O, and Brand W tags as they have the 3 lowest counts and the rest of the tags will be removed, i.e. Brand A, Brand F, and Brand L.

To do this, use 'retain least filled tags' instead of 'add least filled tags'.

1. Click the logic editor in any question/section after Q2: Bought in P12m.
2. Click Add Action Logic
3. In the 'If...' dropdown, input your condition, i.e. if respondent has tags > any of > Brand A, Brand B, Brand C, Brand D, Brand E, Brand F, Brand G, Brand L, Brand O, Brand W, Brand X.
4. In the 'Then...' dropdown, pick 'retain least filled tags'
5. In the 'Tags' dropdown, select the exact same tags you selected in the 'If...' condition (i.e. Brands A to X).
6. In the 'Set amount to least fill' dropdown, pick the max number of tags you want respondents to retain, in this case: 3.
7. Click Save & Close