Comparison and Influence of Two Data Collection Methods on the Results of a Quantitative Survey: This article proposes to analyze and compare two sets of data obtained from the same survey questionnaire by two different methods. In the framework of our research on social workers which includes a quantitative aspect, we used the Internet as a data collection tool along with the more classical method of sending out a questionnaire by mail. This article proposes to consider the different aspects of comparison possible based on a concrete analysis to the two sets of data obtained from the two samples according to a specific variable associated with our research topic. Then, based on a comparative analysis, we examine the cumulative consequences of the mail questionnaire and the Internet questionnaire data and their implications for our research. We also show how the origin of the data can or cannot influence research results.