Quota Control allows you to automatically close the survey to new respondents after a specific number of completed records, or after a certain number of records are completed by specific types of individuals (e.g. males, females). Quota Control is also used to acquire a sample reflecting known characteristics of a population: representative proportions of male, female, low income, high income, etc.
You implement Quota Control by adding a "Quota" to your survey. Quotas are added to the survey by clicking the Add button (similar to how you add questions). Quotas are not seen by respondents. When respondents arrive at the point in the survey where the Quota is located, they are assigned to the quota group they qualify for. If they do not qualify for any of the quota groups, they are skipped to a location in the survey that you specify; often, this is a Terminate question with "Disqualified" set as the status.
Quota Group Value and Label
Each quota group has an assigned value and a label you can use to describe the group. The value associated with the quota group is assigned to the quota question in the data once the respondent qualifies for the quota group. The label is used in reporting etc.
Quota Group Limit
The limit allows you to set the total number of respondents who are allowed to be in the quota group. Once the quota group limit is met, no additional respondents can be assigned to the group. However, it is possible that in some situations you will end up with more respondents in the group than is specified by the limit. See Predictive Control below.
Quota Group Logic
A respondent can qualify for a certain quota group if the limit has not been met and they qualify for the group according to the specified logic.
Selecting the If option allows you to specify logic to determine whether or not the respondent should qualify for the quota group. If the Always option is selected then every respondent will qualify.
Selecting Custom allows you to enter custom logic. This is useful if you need to specify advanced logic. For example, maybe you need to do some simple math, include Sawtooth Script, or use parentheses. See Custom Logic for more information.
Multiple Rows of Logic
If you need to add additional logic, select Add Logic. The additional logic is joined to the logic above it by using And or Or. If "And" is used, both rows of logic have to be true for a respondent to qualify. If Or is used, either of the two rows of logic can be true to qualify a respondent.
Two logic rows joined with an And will be considered together before two joined with Or. This behaves similar to multiplication and addition in basic math order of operations. And behaves similar to the multiply operator and Or is similar to addition. Here is an example:
If Q15 = 5
Or Q15 = 7
And Q16 = 1
If the logic above included parentheses it would be similar to this:
Q15 = 5 Or (Q15 = 7 AND Q16 = 1)
The respondent qualifies for the quota group if Q15 is 5. But if Q15 is not 5, then Q15 has to be 7 and Q16 has to be 1, in order to qualify.
Multiple Quota Groups
Quotas can contain multiple quota groups. A respondent can only be assigned to one quota group. They will be assigned to a quota group only if the specified logic evaluates to true and the group limit has not been met. By default, quota groups are considered sequentially from top to bottom. To change the order that the quota groups are considered see Check for Group Membership Method below.
If you need respondents to qualify for multiple quota cells consider adding multiple quotas to your survey.
Check for Group Membership Method
Respondents can only be assigned to one quota group. To be assigned to a quota group they need to qualify for the quota group logic and the quota group limit cannot be met. By default quota groups are considered sequentially from top to bottom. To change the order that the quota groups are evaluated in, click the Advanced tab and change the Check for group membership method option. Here are the different options:
Sequential
Evaluate and assign quota group membership sequentially starting with the first one and then moving down the list from the top to the bottom.
Least Fill (Percentage)
Assign quota group membership where, if a respondent could qualify for multiple groups, quota groups that are least filled are prioritized. To determine which groups are least filled the number of respondents currently assigned to the quota group is divided by the total number of respondents allowed in the group (the group limit). The groups are then prioritized in percentage order from low to high. If groups are evenly filled then they are considered randomly.
Least Fill (Counts)
Assign quota group membership where, if a respondent could qualify for multiple groups, quota groups that have the least amount of respondents are prioritized, examining only the current quota group counts. The groups are prioritized by the number of respondents currently assigned to the groups from low to high. If groups are evenly filled then they are considered randomly.
Randomize All
Evaluate and assign quota group membership randomly.
Randomize Subset
Evaluate and assign quota group membership randomly within a subset of the range specified. The quota groups outside the range are evaluated sequentially.
Respondents are only counted in the quota group when they finish the survey. Therefore, if multiple people are taking the survey at the same time, it is possible to end up with more respondents in a given quota group than is specified by the limit. The Predictive Control settings can help to minimize this issue.
Here is an example of how this issue can happen: Let's say you are trying to collect 100 respondents who prefer brand A. You have set up a quota group named "Brand A" with a limit of 100 and have already collected 90 respondents for this group. Imagine that 15 respondents enter the survey at the same time. When they reach the quota all 15 respondents prefer brand A and qualify for the "Brand A" quota group. Since respondents are not counted toward the limit until they finish the survey, all 15 respondents are assigned the Brand A quota group. If all 15 respondents end up finishing the survey, the quota group count for Brand A will be 105.
The Predictive Control settings Projected Completion Rate and Time Limit help to minimize this issue. These settings help the system predict that certain respondents assigned to quota groups will finish the survey. As a result, fewer respondents are allowed to be assigned to the quota groups because we are predicting that those already assigned will finish.
Projected Completion Rate
The estimated percentage of incomplete respondents that will finish the survey. For example, if you enter 50%, you are telling the system to assume that 50% of the respondents currently assigned to the quota group (but who have not finished the survey) will finish.
Time Limit
If a respondent last accessed the survey within this time limit, then it is assumed that they will finish the survey. For example, if you enter 30 minutes for the time limit, the system assumes that respondents who have not accessed the survey in the last 30 minutes will not finish the survey.
Both of these settings can be used together to help predict who will finish the survey and reduce quota overage. For example, you could make the system assume that only 50% of those who were assigned to the quota, and have also accessed the survey within the last 30 minutes, will finish.
Sawtooth Script Quota Control Functions
See Quota Control Functions for functions you can use in skip logic etc.