Thanks to some early data from Pizza Girl, of Slice fame, I have some very preliminary findings.

There are a few different ways to tip, check (only one person did this), credit card at the door, pre-tipping with a credit card and cash.  As seen in these boxplots, cash tippers were the highest, on average.  Pre-tippers, who really are just tipping based on feeling, not performance, have the greatest variability.  There was even someone who only pre-tipped a dollar.  Pre-tipping a large amount might be a good idea–kind of like greasing a palm at a restaurant to get a table–but I don’t see how a small pre-tip is a good idea.

I wonder why people give bigger tips with cash than with credit cards.  I would have thought it would be the other way around.

This is just the beginning.  Pizza Girl is providing more data as the weeks go on.  And as I get more data the analysis will become more sophisticated, so stay tuned as we unravel the world of pizza delivery.  In the mean time, check out Pizza Girl’s third installment of her findings on Slice.

Jared Lander is the Chief Data Scientist of Lander Analytics a New York data science firm, Adjunct Professor at Columbia University, Organizer of the New York Open Statistical Programming meetup and the New York and Washington DC R Conferences and author of R for Everyone.