Time-outs and restarts
Time-outs in UNICOM Intelligence Interviewer are based on a default of ten minutes' inactivity. After this delay, end-of-interview happens but with the status set to Timed Out rather than to Completed Interview.
Restarting timed out interviews
While an interview is in progress, the interviewing program stores information about the interview and any interview data gathered so far in a file in the Value Cache. If the interview times out, its value cache file remains in the cache for a certain amount of time in case the interview needs to be restarted. If an interview is restarted after a time-out, the interviewing program uses this file to reconnect to it at the question at which the interview timed out. If the project uses sample management, the sample management system locates the existing data for the interview and makes it available to the interviewing program. Then, the interviewing program silently replays the existing data as if the respondent were taking the interview for the first time. When it reaches an unanswered question, the replay stops and the interviewing program displays that question.
See
Restarting by clicking Next and
Restarting from a URL for more information about the restart process.
Avoiding unnecessary time-outs
To avoid unnecessary time-outs, always ensure that all respondents leave the interview through a proper closing statement such as end or signal. If you terminate interviews by sending respondents to a different URL instead of allowing them to reach a terminating statement in the questionnaire, the interviews will continue to run until they time out. This means that you may have a lot of interviews held in memory when they need not be there.
Changing the time-out delay
You can change the time-out delay in the registry (see
Interviewing settings) or in the sample management script. The registry setting applies to all interviews, whereas the value in the sample management script can vary between interviews or between projects. For example, if you are hoping for detailed open-ended responses, you may want to increase the time-out period to allow sufficient time for respondents to complete their responses. If you are considering changing the time-out value, bear in mind the following when choosing a new setting:
▪If you set the time-out very low (say, one minute), UNICOM Intelligence Interviewer automatically releases the interview object after one minute's inactivity. This releases memory, but also causes other resource-intensive steps to take place. First, the ReturnSampleRec function is run in sample management. Second, if the respondent clicks Next, the interview is restarted. This executes a hidden re-login procedure, creates a new interview object, reads all the data for the interview into memory and then steps through that data until an unanswered question is found.
▪If you set the time-out very high (say, 30 minutes), UNICOM Intelligence Interviewer keeps interviews in memory longer than necessary, which uses up RAM on the interviewing computers. This can lead to disk swapping which can slow down the computers.
See also