Keywords: Response rates, Data quality SMS to web survey, Best practices

In this paper a sequential mixed mode approach for survey data collection using mobile phone numbers is presented which can increase response rates, coverage and improve data quality. The first mode is a SMS to web survey data collection method, which is a convenient and efficient way to gather information with many advantages. However,the method comes with certain disadvantages too. Its most significant drawback is its limited reach for participants without internet access and people who have concerns about following links in text messages they receive on their mobile phones. The second data collection mode includes telephone interviews. Telephone interview surveys are valuable for reaching people without internet access or who are uncomfortable with web surveys and offer many advantages such as higher response rates and cost-effectiveness. The paper includes best practices for both modes to ensure successful data collection, and presents comparisons between the two modes and a description of the resulting structure of the final combined dataset.