Before starting out on this change of venue, they first collected data on the amount of paper hand towels used in the mens restroom for a period of 15 days to work out the average amount of paper towels typically used each day. Once this had been done they then introduced a large recycling bin near the sinks with signs indicating that the restrooms were participating in a paper hand towel recycling program, and that any used hand towels placed in the bin would be recycled. For the next 15 days, they then simply measured the amount of paper hand towels used.
Consistent with their laboratory studies, paper towel usage increased after the introduction of the recycling bin by an average of half a paper towel per person. At first glance this small increase doesn’t seem that big a deal. However, given that the restroom was typically used over a hundred times each work day, the increase in usage was substantial: It totaled about 12,500 paper hand towels annually for this one restroom alone.
Excerpt from: The Small BIG: Small Changes that Spark Big Influence by Robert Cialdini, Noah Goldstein, and Steve Martin