I’ve received a surprising amount of feedback about one particular feature of the survey: the request for the four letters and two digits to generate a personalized reference code. Some people simply find it too personal, but others have suggested that the questions' similarity to those used for security on credit cards and other accounts represents a risk of identity theft.

In response, I have changed the prompts and—as always—you can choose your own random letters or numbers. If this was stopping you from taking the survey, please feel free to go ahead now.

However, I wanted to take a moment to explain what this step is and why, as well as to say something about how we’re protecting your privacy.