3 colleagues of mine wish to use an online device/strategy called Qualtrics to collect and input data to be analyzed using SPSS. A 4th must collect the same data by pencil & paper, then put it in Excel to be delivered to our person who is using Qualtrics. Can we compare the input of the paper & pencil guy with the data collected through Qualtrics. Assuming no significant differences can we then combine the 2 data sets into one? Or, is there a good methodological reason why that should not be done?