Half-open Strata

A quota stratum can be put in one of four states:

When a stratum is Half-open, the system will stop dispatching cases when the number of respondents being interviewed in this stratum reaches the number of completed interviews that remain to complete its quota. This ensures the quota is not exceeded, even by one respondent. To assist the field supervisor, the Quotas tab shows the number of interviewers working in each stratum.

The following rules apply:

  1. A Half-open stratum is ignored when quotas are inactive.

  2. A hard call-back, i.e. initiated from the Call-back command, and taken from the Call-back list, will not be impeded by a half-open stratum. However, the control of active interviewers in the stratum will take it into account, and a soft call-back initiated by the New command will conform to the half-open stratum constraint.

  3. You may simultaneously apply both quota weighting and the half-open status to a stratum. In this situation, if a half-open stratum is temporarily full, it will have a weight of zero; hence it will not be picked randomly. On the other hand, if a case is selected by virtue of its weight, and if it is not available due to the status of another Half-open stratum to which this case belongs, the weighting rule will take priority, and the case will be dispatched anyway.

  4. Half-open strata have no effect on an interview in progress. They only draw on data that has been imported or collected in a previous call.

For all the reasons explained above, a half-open stratum with a quota of 0 is effectively closed.