When analyzing data, the base size describes the total number of respondents that are included when percents are calculated. A simple example is as follows:

In your survey, 60% of your respondents said they're Female, and 40% Male. If 100 people took your survey, your base size is 100. Let's say, you needed to look at a different population, say those who live in the Southeast region. You're base would now be smaller than the total, 100. Adjusting the base from 100 to only those who live in the Southeast would also cause the percents to change. You would no longer have 60% Female and 40% Male.

This example showcases why base sizes matter and also why filtering data, in this case by the Southeast region, will have an effect on your base size and ultimately your percentages.

Now let's discuss how the auto-update base feature works.

The Auto-update Base feature is a helpful way to update the base size as you change your analysis. By default, this option is not enabled. This ensures the experience you’re used to does not change in any way.

The example below is the default experience with no filters applied:

A) Current Base Size

  • The current base size reflects the number of respondents who responded to the first-row question “Generation”.
  • In this example, 2,118 individuals saw the question “Generation”

B) Column Base Size

  • The column base size reflects the number of respondents who responded to the first-row question AND selected that column option.
  • In this example, 373 respondents:
  • answered the question “Generation”
  • selected the option “Computer” when asked, “On what device do you most often watch programs (like TV shows, movies, and videos)?”

When Auto-update Base is Enabled

When the Auto-update Base button is enabled, the base size will be modified to only include respondents who have selected one of the visible options for each variable.

See the below example with no filters applied:

A) Current Base

  • The current base size reflects the number of respondents who responded to the first-row question, and who have selected one of the visible options for each variable.
  • In this example, 1,609 individuals:
  • i. answered the question “Generation”
  • ii. selected Baby Boomers, Generation X or Millennials
  • iii. answered the question “On what device do you most often watch programs (like TV shows, movies, and videos)?” and selected Smartphone, Computer, TV set, or Tablet.

B) Column Base

  • The column base size reflects the number of respondents who responded to the first-row question, and who have selected one of the visible options for each row variable, AND selected that column option.
  • In this example, 233 respondents:
  • i. answered the question “Generation”
  • ii. selected Baby Boomers, Generation X or Millennials
  • iii. selected the option “Computer” when asked, “On what device do you most often watch programs (like TV shows, movies, and videos)?”

A more advanced scenario

In this example, Auto-update Base is enabled AND we have a filter applied on top.

A) Current Base

  • The current base size reflects the number of respondents who responded to the first-row question AND meets the requirements of the applied filter.
  • In this example, 208 individuals:
  • i. answered the question "generation"
  • ii. selected Baby Boomers, Generation X or Millennials
  • iii. answered the question “Household Income” and selected “$100,000-$149,999”.

B) Column Base

  • The column base size reflects the number of respondents who responded to the first-row question, meets the applied filter requirements, AND selected that column option combination.
  • In this example, 36 respondents:
  • i. answered the question “On what device do you most often watch programs (like TV shows, movies, and videos)?”
  • ii. selected “$100,000-$149,999” for Household Income
  • iii. selected the option “Computer”


Cell Base Sizes

In certain cases, you will observe additional information within a cell represented by n=. This is a specific base size for that cell.

The cell base size is a specific base size that differs from other options within the group. For example, sometimes response options may be added while a survey is in field. If this occurs, a different amount of respondents will have even seen that response option. KnowledgeHound ensures you understand this by adding specific base sizes to the individual cell.

This is important because you may see two cells that both say 50%, but one response option may have a base size of 200, while another may have a base size of 50 because it was added to the survey later. Statistically, it is important to call this out.

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