Till recently, standardization was considered the norm in surveys. According to standardization rules, respondents are to be contacted using standardized procedures, interviewed by reading out questionnaire question as scripted and using standardized survey “tools”. However, there is evidence that suggests that, in some contexts, this approach may not be the most effective and alternative approaches to data collection, such as those based on “tailoring” survey instruments to respondent characteristics (i. e., flexible interviewing), may obtain better results. Little is known on the effects of using flexible data collection methods on data quality.
In this paper we report findings from an experiment that evaluates the impact of personalized vs. standardized SMS invitations on two aspects of non-sampling error, i. e., non-response and measurement error. Previous research on this topic has found that personalization of e-mail salutations significantly increases response rate when surveying university students (Heerwegh 2005; Joinson, Reips 2007). However, we are not aware of any studies that also looked at the impact of different ways of phrasing salutations on measurement error. This study is meant to contribute to expand the knowledge in this research field.
We use experimental data collected in the context of a follow-up of a national web survey on occupational outcomes of Italian graduates in Social Work (Sala, Decataldo and Respi 2015) that was carried out in 2015. To invite sample members to take part in the follow-up, short text messages (SMS) were used (telephone numbers were available from the graduates’ administrative records).
Sample members were randomly assigned to two groups: the “standardized” and the “personalized” salutation group. The text of the “standardized” SMS was: “Dear graduate, we are carrying out the second wave of the survey Occupational Outcomes of Social Workers. Take part in the study! Link to the 6 questions [url]”. The text of the “personalized” SMS was different only in the incipit: “Dear [graduate’s name], we are carrying out...”. The invitation was sent on May, 13th 2015.
To assess the impact of the different types of salutations on response and measurement errors  we consider different indicators of survey participation and data quality. Indicators of the former include response rates and speed of response; indicators of the latter include item non response, the time taken to fill in the questionnaire, and social desirability. To analyse our data, we will adopt both bivariate and multivariate analysis.
So far we focused on the first research aim and analyzed the impact of tailoring the salutations of the SMS on survey participation. Results from a preliminary analysis show that there is a difference of 5 percent points in response rates between the two groups; sample members who received the personalized invitation (Dear Jon, for example) are more likely to respond than those sample members who received the standardized invitation (significant at 10% level). In the paper we intend to reflect on the psychological mechanisms that lead these differences.
Keywords: standardization, flexible interviewing, non response error.