Try the randomizer in the survey flow

Can you give me some more detail?

yaozhao it is likely that two is a small ratio for the number of completes you are looking to get. If you had a fixed ratio like 20% win, then you could follow the documentation on the Qualtrics Support page titled Create an Anonymized Raffle.

But I don't think that is your case. I think is likely you don't know the number of completes or that it would be high enough that the percent for 2 divided by your goal completes is very small (making the instructions on the link above tedious). I recommend you collect the data as you have laid out above. And then when fielding is over, you download your data file and use a random function in Excel or SPSS to pick your two winners.