Panda Express Survey Validation Codes and Completion Rate
Panda Express has issued over 82,000 free entree codes to survey
participants as of this writing (February 2009). They issue about
1500 per day. (A list of codes is
here and the survey is
Update: It now seems that they have wrapped around and are reusing
previously-issued numbers. As of February 2010, codes in the 20,600
range are being issued. It seems likely they started over from 10,000
when they reached 99,999 to keep the numbers short and easy to write
Panda Express, a chain of Chinese fast-food restaurants, issues
coupons for a free entree item that require completion of a survey.
Recently after completing a couple of surveys, I noticed that the
validation codes were quite close. Given that the codes were entered
about 15 minutes apart, it seems that the codes are simply increasing
integer indices of the completed survey (1 for the first completed
survey, 2 for the second, and so forth).
Thus we can determine that if 15 minutes elapsed, and if the survey
indices were different by 32, then about 2 people per minute are
completing the surveys. (Assuming a constant completion rate.)
At 2 people per minute, that works out to 60 * 24 * 2 = 2,880 survey
completions per day. That's probably a little high, since people
probably fill out fewer surveys in the middle of the night or in the
morning. So figure about 1500 surveys are completed per day.