New York, Nov 13 (IANS): Offering customers the opportunity to make charitable donations to good causes along with a moderate discount for their purchases doubles sales, says a study.

"The mere presence of a charitable donation opportunity can generate significantly more sales," said one of the study authors Michelle Andrews from the Temple University in the US.

"Offering the donation nearly doubled the number of purchases," Andrews added.

With the help of a participating mobile service provider, the study authors sent two messages to customers.

The first version advertised tickets for a new film at a nearby theatre, and the second advertised the tickets with a note saying that part of the proceeds would go to help low income students pay for college.

The results were significant: those people believing their purchase would help others were far more inclined to make a purchase.

The authors also found that offering a moderate discount along with the charity message resulted in the best sales.

A moderate discount made customers feel that they were being taken care of, and that in addition to that the company was making sacrifices for a good cause.

The study appeared in the Journal of Marketing.