Using visual analogue scales in ehealth: Non-response effects in a lifestyle intervention

Background: visual analogue scales (vass) have been shown to be valid measurement instruments and a better alternative to likert-type scales in internet-based research,both empirically and theoretically [1,2]. upsides include more differentiated responses,better measurement level,and less error. their feasibility and properties in the context of ehealth,however,have not been examined so far. objective: the present study examined vass in the context of a lifestyle study conducted online,measuring the impact of vass on distributional properties and non-response. method: a sample of 446 participants with a mean age of 52.4 years (standard deviation (sd) = 12.1) took part in the study. the study was carried out as a randomized controlled trial,aimed at supporting participants over 8 weeks with an additional follow-up measurement. in addition to the randomized questionnaire,participants were further randomly assigned to either a likert-type or vas response scale version of the measures. results: results showed that sds were lower for items answered via vass,2p (y ≥ 47 | n=55,p=.5) <.001. means did not differ across versions. participants in the vas version showed lower dropout rates than participants in the likert version,odds ratio = 0.75,90% ci (0.58-0.98),p=.04. number of missing values did not differ between questionnaire versions. conclusions: the vas is shown to be a valid instrument in the ehealth context,offering advantages over likert-type scales. the results of the study provide further support for the use of vass in internet-based research,extending the scope to senior samples in the health context.