Acupuncture expectancy scale: development and preliminary validation in China

Expectancy has been shown to affect the response to psychological and medical interventions; however, the lack of validated measure of expectancy in the setting of acupuncture limits the quantitative evaluation of the effects of expectancy on clinical response to acupuncture therapy. We seek to develop and validate an instrument that measures patients' expected response from acupuncture.

We developed the acupuncture expectancy scale by eliciting items from patients and then conducted a survey study in two phases to test the reliability and validity of the instrument among 200 subjects at six outpatient acupuncture clinics in Beijing, China.

Our final scale consisted of four items measuring the expectation of improvement of illness, enhanced coping, increased vitality, and symptom alleviation as a result of acupuncture therapy. Scores of acupuncture expectancy scales ranged from four to 20, with a median of 17, and 21% at the maximum score. No item had over 5% missing data. Internal consistency (Cronbach's alpha coefficient) was .82. Principal components analysis revealed one general component accounting for 64% of the variance. Expectancy of response was positively correlated with selected questions of perceived efficacy (0.44), satisfaction (0.49), and confidence in prescribed acupuncture therapy (0.51), all with P < .001.

We developed a simple four-item instrument with valid and reliable score that measures expectancy about acupuncture therapy and correlates to subject reported response. The reliability and validity of acupuncture expectancy scale score needs to be tested in other types of populations. Incorporating this instrument in clinical trials can evaluate the role of expectancy as part of the complex social-behavioral component of acupuncture therapy.