Sawtooth Software: The Survey Software of Choice

SSI Web v5.2 Even Better with Quota Control

We are working hard to make SSI Web your software of choice for both general web interviewing and for projects that include conjoint sections. Many of our conjoint analysis customers have been pleasantly surprised with the capabilities of our general interviewing component, CiW. They’ve been able to save money and time by using CiW.

Given our move to administer more research in-house, the cost savings that we are recognizing from doing this with SSI Web is staggering. We have already saved about $100,000 by doing this ourselves with your software rather than hiring outside consultants, and I only expect the trend to conduct more internet surveys (using your hosting services) to increase.

--Tim Glowa,
Staff Analyst, Market Research,
Reliant Energy

Back in October, we released SSI Web v5, which was a major improvement in our web interviewing platform. We had originally planned for Quota Control to be part of that release, but were unable to include it then. In May, we released v5.2 (a free update for v5 users) with Quota Control functionality.

The desire for Quota Control can be economic: respondents completing the survey are paid a cash incentive, and the researcher does not want to go over-budget. Quota Control is also used to achieve a sample reflecting known characteristics of a population: representative proportions of male, female, low income, high income, etc. Using Quota Control can also help us conserve our relationship with respondents: we limit the amount of time we ask of respondents to a few screener questions if we do not need their completed record.

Consider a B-to-B study, wherein the researcher wants to interview 1000 total respondents, with a certain number of completes within different company sizes (large, small) and types (manufacturing, services):

Quota Cell Definitions: Quota Cell Limits:
Large Company, Manufacturing N=400
Large Company, Services N=300
Small Company, Manufacturing N=100
Small Company, Services N=200
   
Total: N=1000

A respondent starts the survey and is first asked what size and type company she works for. These are called screener questions. After screener questions are asked, a determination is made (at the Qualification Point) whether this respondent is needed. If this respondent's Quota Cell is already filled with enough completed records, then she is immediately skipped to the end and disqualified. Otherwise, she is allowed to continue the survey. This process is represented by the diagram below:

SSI Web's quota control is flexible and powerful. Quota membership may be based on many variables, resulting in a virtually unlimited number of quota cells. Screener variables can be "passed in" through a URL link or asked at the beginning of the questionnaire. Quota control cannot guarantee that the quotas you establish for groups are not exceeded. There may be some overage. For example, you may wish to interview just 100 males. A simple rule would be to let males continue the survey if you haven't yet achieved 100 completed male records. Imagine that 99 males have already completed the survey and five males are currently in process (have passed the Qualification Point and are in the middle of the survey), but these five haven't yet finished the survey and been counted as complete. A new male respondent reaches the qualification point, and is allowed to take the survey (since only 99 complete records have been recorded). We can see how this could result in 105 completed records, if all the respondents in process eventually complete the survey.

Predictive Quota Control

SSI Web has more sophisticated rules for determining if the Quota Cell Limit has been or is expected to be reached. You can specify that SSI Web should assume that, say, 80% of the respondents who have passed the Qualification Point and are actively taking the survey will eventually finish (i.e. a 20% drop-out rate). You can also specify that respondents who haven't completed the survey within a certain amount of time should be marked as Inactive.

If these options are in place, when a new respondent reaches the Qualification Point, SSI Web considers the number of respondents in this respondent's quota cell already completed and actively in process (discounted by 20%) to decide if the new respondent is needed. We refer to this ability to more intelligently determine if more respondents are needed within a Quota Cell as Predictive Quota Control. Predictive quota control can certainly limit the amount of overage, but it still cannot ensure that quota cell limits are not exceeded.

Download a Free Demo Version Today

Download a functioning demo version at www.sawtoothsoftware.com/ssiweb.shtml.