unstackby and unstackfor

Use the unstackfor (alias stackfor) and unstackby (alias stackby) tags when building lists with "stacked" data in your survey. This allows reports to automatically display questions using the stacked data with the full brand list "unstacked" rather than the stacked proxy list.

The unstackfor tag identifies the full parent list being stacked. The unstackby tag explicitly indicates which survey variables are storing the values for the list being stacked.

setlist: BRANDS_B
1. Unstackfor is typically used on very long lists.
2. Acer
3. Apple
4. Dell
5. HP

1B. Select the brands you are familiar with.
type: checkbox
optsfrom: BRANDS_B

2BRANDS_B. 2 Brands Respondent is familiar with
type: checkbox
selectby: counts
maxgroups: 2
optsfrom: Q1B

BR1_B. First Brand
type: coded single select
selectby: calculate
cvalue: $Q2BRANDS_B ->[0]
optsfrom: BRANDS_B

BR2_B. Second Brand
type: coded single select
selectby: calculate
cvalue: $Q2BRANDS_B ->[1]
optsfrom: BRANDS_B

setlist: SEL_BRANDS
unstackfor: BRANDS_B
unstackby: QBR1_B, QBR2_B
101. $QBR1_B_text {if anyChecked($QBR1_B)}
102. $QBR2_B_text {if anyChecked($QBR2_B)}

block: <<END

2B_%%ID%%. Would you recommend %%TEXT%%?
type: radio
desc: Recommend | %%TEXT%%
1. Yes
2. No

3B_%%ID%%. Why?
type: radio
desc: Why recommend | %%TEXT%%
1. My personal experience
2. Somebody else's experience I heard about.

END
list: SEL_BRANDS

Details

• Add the unstackfor tag directly on the stacked proxy list. In the above example, this would be the SEL_BRANDS list.

• The input for unstackfor is the parent list. This would be the full brand list, BRANDS_B.

• Add the unstackby tag on the same stacked list as unstackfor. The inputs for unstackby are the variables where each brand (or item being stacked) is selected. This would be QBR1_B and QBR2_B. 
• The stacked list options are the piped values from the variables referenced by unstackby, for example '$QBR1_B_text' and '$QBR2_B_text'.
• The option IDs for the stacked list cannot overlap with the parent list.
• Lists that use unstackfor/unstackby do not support the order, randomize, or alphabetize tags. Apply any ordering tags to the parent list instead.
• A stacked list (such as SEL_BRANDS) cannot be called by a question or table via an optsfrom tag.
• unstackfor can also be written as stackfor; unstackby can also be written as stackby.

Reports

Reports and exports automatically expand stacked fields. They display the questions built from a stacked list using unstackfor/unstackby as if each had a separate data location. 

Without using these tags, creating a stacked list like SEL_BRANDS would result in a very different data output. See the comparison below.

Stacked data without 'unstackfor'	Stacked data with 'unstackfor'

Exporting stacked data

When using the unstackfor tag, deliverable exports expand the stacked fields by default, which helps analysts unstack the data. However, you can export fields as stacked data instead by deselecting the Expand stacked fields checkbox in the Advanced Export Options menu.