Comparability
This variable is fully comparable across time. There is a slight difference in the wording of the questionnaire between 2002 and 2012. In 2002, the question read "During the past 12 months, were any of the costs of using biofeedback covered by insurance?" In 2012, the question read "During the past 12 months, were any of the costs of seeing a practitioner for biofeedback covered by health insurance?"
