Advanced Quota Control Settings

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In the previous sections describing Quota Control, we've emphasized that it is probable that you will actually get more completed records within each Quota Cell than specified in Cell Limits.  This is especially the case if you simultaneously invite a large number of individuals to complete the survey.  For example, if you wait to close a Quota Cell until the last respondent qualifying for this cell has completed the survey, there may be a number of respondents In Progress who eventually complete the survey.  You will exceed your Cell Limit by these respondents still In Progress.

 

The settings on this dialog let you fine-tune the decision rules (Predictive Quota Control) for determining if the Cell Limits have been, or are predicted to be, reached.  The best settings for your project depend on a number of factors, the most significant being the rate at which respondents enter the survey.

 

Do not use Predictive Quota Control

Allow respondents qualifying for a quota cell to continue If the quota limit has not been completely filled

 

The simplest rule is to allow respondents qualifying for a Quota Cell to enter and complete the survey until the number of completed respondents within that Quota Cell reaches the Cell Limit.  Of course, this leads to the greatest likelihood of overage.  But, it also fills the quota cells the fastest.  

 

Use Predictive Quota Control

Allow respondents qualifying for a quota cell to continue if the number of completes plus "in progress" respondents that qualify for the quota cell is less than the quota limit

 

When you check this option, Lighthouse Studio takes into account In Progress respondents when deciding whether new respondents entering the survey are needed to fill the Cell Limits.  This approach reflects Predictive Quota Control.  By counting all or a percentage of In Progress respondents toward the Cell Limit and not counting Inactive respondents, you can significantly reduce the overage on Cell Limits.  This leads to the distinction between a quota cell that is full versus one that is closed.  A quota cell is full when the number of completed respondents reaches the Cell Limit.  A quota cell is closed when the Cell Limit has been reached or when it is projected to be reached by the number of completes plus In Progress respondents.

 

With Predictive Quota Control, the Cell Limits may take longer to fill than when letting all new respondents enter the survey until enough completes are achieved.  But if overage is costly, the tradeoff is usually preferable.  As an illustration, if some In Progress respondents projected to complete the survey don't actually finish, you may have turned new respondents away that you later realize were actually needed.  The settings on this Advanced tab help you reduce the overage while filling Cell Limits relatively quickly.

 

In general, we suggest you use settings that reduce the likelihood of turning new respondents away, fill quota cells quicker, and result in only modest overage of Cell Limits.

 

Use time limit

 

By default, Lighthouse Studio counts all respondents who have passed the Quota question but have not yet completed the survey as In Progress.  But, by checking the Use time limit box, you can specify a specific number of minutes to transpire (since the respondent has qualified for a quota cell) after which the respondent will be marked as Inactive rather than In Progress.  By identifying which respondents are Inactive and highly unlikely to complete the survey, you can distinguish these from the In Progress respondents and allow new fresh respondents to begin the survey.  (Respondents who have quit the survey can later restart if their quota cell is not filled.  Note: respondents can restart even if their quota cell is closed, but not filled.)

 

Larger Time Limits fill quota cells slower, but result in less overage.  For example, if you specify a very long Time Limit of 120 minutes, it could take up to two hours (depending on the Projected Completion Rate) until a replacement is sought for an In Progress respondent who quits the survey.  If you are uncertain regarding a Time Limit, we suggest trying about 30 minutes (for a survey that takes on average 10 to 15 minutes).

 

Use projected completion rate

 

Assigning a Projected Completion Rate to In Progress respondents allows Lighthouse Studio to make more intelligent decisions regarding whether to close or open a Quota Cell.  Typically, about 60-90% of respondents that answer the first few questions eventually complete the survey.  This also means that around 10-40% drop out.  By only counting a fraction of the respondents In Progress toward the Cell Limits, you are less likely to turn away new respondents that you actually need.

 

Larger Projected Completion Rates fill quota cells slower, but result in less overage.  Imagine that you project that 90% of In Progress respondents will complete the survey and only 60% actually do.  Until the Time Limit expires for respondents who quit so they are marked as Inactive, new respondents will have been turned away that could have been used to fill the quota cell.  If you are uncertain regarding a Projected Completion Rate, we suggest trying about 60%.

 

Check for cell membership

 

If your Quota Cells aren't mutually exclusive (if respondents can qualify for more than one Quota Cell), you'll want to consider the order that Lighthouse Studio evaluates the Quota Cells and Qualification Logic.  By default, Lighthouse Studio checks Sequentially for Quota Membership.  Lighthouse Studio starts at the top of the Quota Cell table (on the Cells tab) and works down the list.  The respondent is assigned to the first Quota Cell for which she qualifies.

 

Sometimes, (if respondents can qualify for multiple cells) you may want to fill quota cells randomly.  

 

Sequentially

Evaluate and assign quota cell membership sequentially, from top to bottom of the table specified in the Cells tab.

 

Randomize all

Evaluate and assign quota cell membership randomly, with probability of assignment proportional to quota cell limits.

 

Randomize subset

Evaluate and assign quota cell membership randomly (with probability of assignment proportional to quota cell limits) within a subset of the range of quota cells from the table specified in the Cells tab.  Those quota cells outside the range are evaluated sequentially.

 

Page link: http://www.sawtoothsoftware.com/help/lighthouse-studio/manual/index.html?predictivequotacontrol.html