Recruiting a Probability-Based Online Panel via Postal Mail: Experimental Evidence

Carina Cornesse,Marina Fikel,Ulrich Krieger,Barbara Felderer,Annelies G Blom

doi:10.1177/08944393211006059

Abstract

Once recruited, probability-based online panels have proven to enable high-quality and high-frequency data collection. In ever faster-paced societies and, recently, in times of pandemic lockdowns, such online survey infrastructures are invaluable to social research. In absence of email sampling frames, one way of recruiting such a panel is via postal mail. However, few studies have examined how to best approach and then transition sample members from the initial postal mail contact to the online panel registration. To fill this gap, we implemented a large-scale experiment in the recruitment of the 2018 sample of the German Internet Panel (GIP) varying panel recruitment designs in four experimental conditions: online-only, concurrent mode, online-first, and paper-first. Our results show that the online-only design delivers higher online panel registration rates than the other recruitment designs. In addition, all experimental conditions led to similarly representative samples on key socio-demographic characteristics.

Highlights

Once recruited, probability-based online panels have proven to enable high-quality and high-frequency data collection
The highest online panel registration rate was achieved by the online-only group (24.5%), followed by online-first (22.8%), concurrent mode (22.4%), and paper-first (21.1%; see Figure 3; for more detailed information, including confidence intervals for all response rate estimates, see Table A2 in Appendix A)
Panel registration rates were higher in the two groups that promoted the online survey versions at the previous recruitment survey stage than in the two groups that put more emphasis on the paper questionnaires at the recruitment survey stage

Summary

Introduction

Probability-based online panels have proven to enable high-quality and high-frequency data collection. Few studies have examined how to best approach and transition sample members from the initial postal mail contact to the online panel registration. Online panel recruitment and surveying are typically conducted in two separate, bi-modal stages: A probability sample of the general population is first approached in an offline mode For this initial offline contact with the sample members, face-to-face interviews, postal mail contacts, or a mix of contact modes which may include telephone calls are typically used (see Callegaro et al, 2014). Contacted sample members have to be transferred to the online mode for online panel data collection This can, for example, be done by requesting sample members’ email addresses for further contact or by asking them to follow a website link to a registration page. Regardless of how initial contact is established, many probability-based online panels implement two surveys during their recruitment process: first, an initial recruitment survey during the offline contact (e.g., to ask for an email address); second, a subsequent online registration survey to collect consent to becoming a member of the online panel and additional background information (for examples of such recruitment processes with two surveys, see Blom et al, 2016; for a counter-example that skips the offline recruitment survey, see Høgestøl & Skjervheim, 2014)

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Discussion

Conclusion