Professor Frank Sander was a leading expert on alternative methods of dispute resolution and is one of the pioneers of the field. Among other innovations, one of his early papers put forth the idea of the "Multi-Door Courthouse," a court system that helps direct disputants to the most appropriate route to resolution. Multi-Door Courthouse systems are presently in use in the United States in Colorado, Georgia, Massachusetts, Texas, and Washington D.C., among other places, and internationally in Nigeria and Singapore.