ahh. ok, I see--because the RT for the last thought is scored as missing? One way you could deal with this is to request a time stamp at the start of the thought listing and another at the start of the next item. You could take the difference between the two stamps as the total thought listing time.

For more info on timestamps, see:
www.empirisoft.com/medialab/help/queparameters.htm#timestamp

Or, you could put the thought listing question in as its own questionnaire. The question_order.csv file in the byVariableName data folder will tell you the start time of each questionnaire so you could calculate it that way also.

For more on the question_order.csv file, see:
www.empirisoft.com/medialab/help/data_faq.htm#data_viewdata