According to a new study released by the Mayo Clinic, drying hands with a paper towel is more effective when compared with cloth towels and electric air dryers. The study, conducted last year, reviewed 12 studies on the hygienic efficacy of different hand drying methods. According to the study, "The risk of potential contamination among dispenser exits, paper towels, and hands should be considered in the design, construction, and the use of paper towel dispensers."
This website article also linked to the actual study completed by Mayo, which I read through a bit. Mayo Clinic was very particular in which studies they would use for their study. Studies had to compare the hygiene performance of at least 2 hand-drying methods. Second, studies had to use an empirical research approach with quantitative outcomes; qualitative and review articles were excluded. I think these approaches were very important to the outcome of the study. Their approaches made their research valid and reliable, and ultimately credible to people who read the article.
The full research article: http://www.mayoclinicproceedings.org/article/S0025-6196%2812%2900393-X/fulltext