Pre-populate web surveys using URL variables

Problem: You want to connect what you already know about a respondent to a new web data collection.
One Solution: URL Variables
URL variables are by no means the only way to pre-populate data but they are one way. The premise is simple, you add data to the end of your survey’s invitation web link giving each respondent a unique URL. When a respondent clicks on the special link not only will they go to the survey, they will also find it pre-populated with data.
The most common use of URL variables is to populate an ID variable. But you can use the method to pre-populate all sorts of questions and even pre-populate hidden variables the respondent will never see. The amount of flexibility you have will depend on the survey application you are using.