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Coded variables

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Coded variables are hidden questions with a built-in selection or calculation process for single select, multi-select, and numeric input questions. They are created using the type: coded single select, type: coded multiple select, or type: coded number tags, respectively.

1. Do you have any of the following food allergies?
instruct: Select all that apply.
type: checkbox
randomize: y
1. Tree nuts (almond, cashews, walnuts)
2. Peanuts
3. Milk / Dairy
4. Eggs
5. Wheat and/or Gluten
6. Fish
7. Soy
99. I don't have food allergies {exclusive: y}

FISHALLERGY. VAR | Allergic to Fish or NOT
type: coded single select
1. Yes, allergic to fish {if anyChecked($Q1,6)}
2. No, NOT allergic to fish {if noneChecked($Q1,6)}

Details

  • Coded single select and coded multiple select variables have selectby: condition built into them. Unless the selectby method is modified, each option in the variable requires a condition.
  • To use a different selectby method with a coded single select or coded multiple select variable, include a selectby tag specifying another input, e.g., selectby: weights.
  • A coded number variable is a numeric question type that includes the invisible tag.  A cvalue tag can be included on coded number variables to specify logic or mathematical equations for calculating the value stored by the variable.
  • Quotas and click balance quotas (CBQs) can be created from coded variables by including the quotas: y and click balance quotas: y tags, respectively.

Type and properties

Type Properties
coded single select type: radio
selectby: condition
coded multiple select type: checkbox
selectby: condition
coded number type: number
invisible: y

Commonly used tags

Tag Description Use with
click balance quotas Set to 'y' to create a "click balance quota" (CBQ) from a question. CBQs are based on all incoming traffic, instead of completes like a regular quota. coded single select and coded multiple select
cvalue

Calculates and sets a value for a coded number variable or when a single or multiple select coded variable uses selectby: calculate.

cvalue accepts any logical statement or Perl expression for input.

 coded number variables, or when using  selectby: calculate with closed end coded variables
maxgroups Sets a maximum number of options or groups that a respondent may be assigned to if they meet the condition criteria. coded multiple select variables
export unseen options as Renders options unseen by respondents as '"blanks" in data exports rather than '0'. The input options are '0' (default) and 'blank'. coded multiple select variables
quotas Set to 'y' to create a quota variable from a question based on the number of completes. coded single select and coded multiple select
selectby

Specifies how to assign respondents to a group when they may qualify for more than one. Common selectby methods include: 'counts', 'weight', 'condition', 'random', and 'calculate'.

The selectby tag will accept multiple methods – e.g., selectby: weights, counts – but selectby: calculate cannot be combined with others.

 all coded variable types

Additional examples

For the purposes of this article, we will use an extended example to illustrate various ways in which coded variables can be created. The examples that follow will reference the survey code below. Each section will highlight a specific part to demonstrate how the coded variable is created.

The following set of questions asks respondents for their familiarity with and usage of various grocery stores, examining whether they tend to use "supermarkets" or "club/warehouse" grocers more frequently. 

set list: STORES
randomize: y
1. Market Basket
2. Price Chopper
3. Price Rite
4. ShopRite
5. Tops
6. Weis Markets
7. Wegmans
8. BJ's Wholesale Club
9. Costco
10. Sam's Club

1. Which of the following stores have you ever heard of?
type: checkbox
optsfrom: STORES

2. Which of the following stores have you shopped at in the last year?
type: checkbox
optsfrom: STORES {if anyChecked($Q1,[id])}
99. None of the above {exclusive: y}

HEARD. Stores heard of but never shopped
type: coded multiple select
optsfrom: STORES { if anyChecked($Q1,[id]) and noneChecked($Q2,[id]) }

3. What percent of your shopping is done at each of the following stores?
type: integer table
postfix: %
range: 0-100
rowsfrom: STORES { if anyChecked($Q2,[id]) }
show column total: <b>Total</b> {total: 100} {message: Please ensure you responses add up to 100%.}

GT10. Stores where at least 10% of shopping done
type: coded multiple select
optsfrom: STORES {if $Q3R[id]>=10}

PRIMARY. Store where majority of shopping done
type: coded single select
selectby: weight
optsfrom: STORES {weight: $Q3R[id]}

TOP2. Top 2 Stores where shopping done
type: coded multiple select
maxgroups: 2
selectby: weight, counts
optsfrom: STORES {weight: $Q3R[id]}

CLUB. Is primary store club or grocery?
type: coded single select
1. Supermarket {if anyChecked($QPRIMARY,1..7)}
2. Club / Warehouse {if anyChecked($QPRIMARY,8..10)}

CLUB1. Is primary store club or grocery?
desc: Same as QCLUB but using calculate and cvalue
type: coded single select
selectby: calculate
cvalue: if ($QPRIMARY<8) {1} else {2}
1. Supermarket
2. Club / Warehouse

TOTAL_SPEND_GROCERY. Total Spend at Grocery Stores
type: coded number
cvalue: listSum(STORES [1..7]; $Q3R[id])

TOTAL_SPEND_CLUB. Total Spend at Club Stores
type: coded number
cvalue: listSum(STORES [8..10]; $Q3R[id])

Applying conditions on a list call

Condition decorators can be applied to a listcall to specify which options should be included in a coded single select or multiple select variable. In this example, QHEARD stores all options that were selected in Q1 (stores they'd heard of) but didn't select in Q2 (hadn't shopped at).

HEARD. Stores heard of but never shopped
type: coded multiple select
optsfrom: STORES { if anyChecked($Q1,[id]) and noneChecked($Q2,[id]) }

Overriding default selectby inputs

To use a different selection method than 'condition' for coded single select or multiple select variables, add the selectby tag to your variable with a different input. Specify multiple selection methods by separating the inputs with a comma. For QTOP2, if there is a tie in the weight for two or more stores, the store with the lowest counts will be selected.

PRIMARY. Store where majority of shopping done
type: coded single select
selectby: weight
optsfrom: STORES { weight: $Q3R[id] }

TOP2. Top 2 Stores where shopping done
type: coded multiple select
maxgroups: 2
selectby: weight, counts
optsfrom: STORES { weight: $Q3R[id] }

 

When using selectby: calculate, include the cvalue tag to specify how values are calculated. In the STORES list, all Supermarkets have an option ID less than 8, while Club/Warehouse stores have options IDs of 8 and above.

CLUB1. Is primary store club or grocery?
desc: Same as QCLUB but using calculate and cvalue 
type: coded single select 
selectby: calculate 
cvalue: if ($QPRIMARY<8) {1} else {2} 
1. Supermarket 
2. Club / Warehouse

Calculating coded number variables

To define a coded number variable, include the cvalue tag with a mathematical or logical expression.

TOTAL_SPEND_GROCERY. Total Spend at Grocery Stores
type: coded number
cvalue: $Q3R1 + $Q3R2 + $Q3R3 + $Q3R4 + $Q3R5 + $Q3R6 + $Q3R7

 

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