Protocol for a web survey experiment studying the feasibility of asking respondents to capture and submit photos of the books they have at home and the resulting data quality

This document presents the protocol of a study conducted as a part of the WEB DATA OPP project, which is funded by the H2020 program. The study aimed to investigate different aspects of the collection of images through web surveys. To do this, we implemented a mobile web survey in an opt-in online panel in Spain. The survey had various questions, some of which were about the books that the participants have at their main residence. The questions related to books were asked in three different ways: regular survey questions showing visual examples of how different numbers of books fit in a 74 centimetre wide shelf depending on their thickness, regular survey questions without the visual examples, and questions where participants were asked to send photos of the books at their home. This report explains how the study was designed and conducted. It covers important aspects such as the experimental design, the questionnaire used, the characteristics of the participants, ethical considerations, and plans for disseminating the results.

This document presents the protocol of our study asking respondents for information about the books they have at home. This information was solicited through conventional types of questions ( i.e., typing in answers or choosing one answer category), and/or through asking respondents to take and send photos of the books.

This study has methodological and substantive objectives. The former involves investigating respondents' preference, evaluation of the questions, participation levels, compliance, and data quality. The latter focuses on exploring the impact of the number of books on the academic achievement of children and examining other factors that might influence these relations.

We conducted a mobile web survey, assigning respondents to four groups:

   •   Choice: Respondents could choose their preferred answering method.

   •   Text-TextPlus: Respondents answered conventional questions first, and later received illustrations of how different numbers of books looked like to help respondents provide accurate answers.

   •   TextPlus-Images: Respondents answered conventional questions with the illustrations and then submitted photos of the books at home.

   •   Images-Text: Respondents shared photos of the books and then answered the conventional questions.

Respondents were asked to evaluate their respective answering methods. The questionnaire had up to 65 questions covering various dimensions, including respondents' sociodemographic characteristics, children's academic performance, literacy-related activities, and camera usage.

Data were collected using the Netquest opt-in online panel in Spain. The tool WebdataVisual was used to capture and share the photos. The target population included parents of children living with them and who attended the first, third, or fifth year of primary school. The sample size was 1,202 cases.

We expect this study to provide valuable insights regarding visual data collection through web surveys. Further, we expect to gain a better understanding of the data on the books respondents have at home when such data are collected through different methods.