These are the raw data as a .csv file used in the manuscript "Uplift gratuity: Effects of an Opportune Gift and its Timing on Tipping Behavior" by Frederic Hilkenmeier, Sascha Hoffmann, and Grzegorz Derkowski.

The study analyzes the timing of a small gift offered by waiters on tipping behavior, showing that customers generously reciprocate a gift by significantly increasing gratuity. Closer temporal proximity between gift and payment even doubles this effect, indicating that servers can substantially - and effortlessly - raise their tips just by manipulating the saliency of the reciprocity norm.

Statistical Analysis: ANCOVA IV: Experimental Condition DV: Gratuity_percentage Covariate: Billsize

As described in the manuscript, we also provide a Reduced Dataset with only 54 subjects (dinner parties) per condition.