3.1 General characteristics of the data collection

Executing entity

Given ELSOC’s quality and transparency standards, an independent institution implemented ELSOC, after a public tender award. We have had three public tenders: in 2016, 2018 and 2020, each covering two study measurements. That is, waves 2016 and 2017 (Original Sample), waves 2018 and 2019 (Original and Refreshment Samples), and waves 2021 and 2022 (Original and Refreshment Samples), respectively.

The Micro-Data Center (CMD) of the Faculty of Economics and Business at the University of Chile has won the three tenders, so it has been in charge of the development of the survey since its beginning. The bidding conditions and agreement with CMD contemplate the highest quality standards and assure adequate protection of the personal contact data from study participants.

We describe below some of the criteria and practices applied to ensure the quality of data collection and processing:

Questionnaire pilot

Each pilot of ELSOC questionnaire followed the ELSOC survey mode to test the instrument and evaluate the operational performance of the survey.

The pilot is carried out in the months before the official survey, followed by a round of focus groups with the interviewers to obtain relevant recommendations for the final study. We use the information obtained to introduce changes to the questionnaires and define adjustments to the interviewer training program.

We use a random sample from the Metropolitan Region for the pilot process, obtained from the census developed by the CMD for the original sample.

Fieldwork planning and execution

The selection and training of site coordinators, interviewers and supervisors is a fundamental pillar of the survey. Therefore, it is essential that both coordinators and interviewers fully understand the study and its objective so that they can argue the importance and functionality of the information they are collecting.

A first step is the selection of Site Coordinators, who are in charge of leading the team of interviewers in each administrative zone (sites). We select people with experience in this position in previous waves of the project and/or with expertise in complex surveys.

In the case of interviewers, we invite those who had participated in previous waves, and the evaluation of their work was satisfactory. We also asked interviewers who had participated in the CMD’s last survey projects.

For each data collection process, we train interviewers and supervisors on aspects of the study (objectives, coverage, types of interviewees, etc.), methodological characteristics of the application format and the questionnaire.

Additionally, we developed and used an Interviewer’s Manual for Implementing ELSOC, guidance documents and protocols for the application of the questionnaire. These include:

  • Visit Protocol: first contact with the house, first contact with the household and arranging interviews when it is not possible to interview at the time of the visit.

  • Complex Case Protocol: scenario of refusals, the scenario of more than four face-to-face attempts without contact, barriers to access to the household, no contact with the household. It also contemplates recuperation strategies.

  • Questionnaire Application Protocol: description of the study, informed consent, application of questions, handling of interruptions, delivery of gift cards.

  • Field Protocol: information backup, progress control, contact registry.

We adapted the documents to meet the follow-up requirements of a previously interviewed sample.

Fieldwork quality control and assurance

From the beginning of the survey and throughout its execution, supervision and quality control strategies are constantly carried out, aimed not only at monitoring the progress of the study but also at detecting early and in real-time errors that occurred during the survey, behavioural problems among the interviewers, among other aspects.

We have implemented the following early warning strategies and corrective measures during the survey process:

  • The site coordinator reviews 100% of the surveys collected in terms of the observations recorded by the interviewer. This stage verifies that the person chosen in the sampling process has actually been interviewed and confirms the correct filling out of the route sheet, schedule and duration of the interview.

  • We supervise surveys collected by people other than the team of interviewers who conducted the registry. For this purpose, a randomly selected percentage of the sample (between 10 and 25% of the complete sample, depending on the wave) is re-contacted to verify the answers to key questions, detect and correct in time any possible biases of the interviewer team, application errors, and potential serious faults such as falsification of the surveys.

  • Weekly feedback to interviewers from zone chiefs, based on survey review and supervision results.

  • Ongoing verification of the information collected by the central team to the database and validation registry.

  • Weekly report to the COES team informing on the state of progress of the survey.

Monitoring Strategy

An essential aspect of ELSOC’s ongoing operation is to ensure that we follow up with the interviewees selected in the sample over time. Therefore, we defined loyalty and monitoring strategies to reduce attrition.

Some of the measures implemented are:

  • Obtaining, saving and updating relevant information to ensure adequate contact: name of the interviewee, contact information (telephone number and e-mail), and essential aspects for identification. We save and use this information following strict confidentiality standards.

  • Conduct pre-contact to arrange interviews and plan the field before the survey date. Each interviewer receives from the site coordinator data on appointments made with ELSOC participants and uses a specific interview protocol for re-interviews.

  • Formation of teams of interviewers with varied profiles, favouring those with experience in previous waves of ELSOC or other complex surveys. The interviewers and coordinators are trained in elements specific to the position and technical aspects of the questionnaire and the study, emphasising the interview protocol.

  • Use of letters of introduction for each interviewee, signed by the Director of the Microdata Center, explaining the study’s objectives, the institutions in charge, the guarantee of confidentiality of the data and the granting of an incentive.

  • Grant a monetary incentive to the interviewees after completing the survey. The incentive is a Giftcard for supermarkets or related businesses. The incentive was $6,000 during the 2016, 2017, 2018 and 2019 waves. During the 2021 wave, the monetary incentive was increased to $9,000.

  • Re-contact in the event of rejections or reach problems with interviewers other than the original one, who must have a profile appropriate to the observed characteristics of the not achieved sample and more significant experience in applying similar surveys. These interviewers have an additional economic incentive to implement surveys defined as “recovered”.

  • In cases where the respondent has moved, we ask the interviewers to inquire about the new address and make efforts to interview the respondent at the new address. This applies both to address changes at the commune level in the same region, or another commune in a different region. In the latter case, they forward the folio to the coordinator in charge of the respondent’s new commune of residence.

  • Christmas greetings or similar gestures are sent to ELSOC participants by e-mail on relevant dates. In addition, we provide brochures with the main results of previous waves so that interviewees know about the uses of the collected data and its relevance to the country.