Where	A/N	=	all or nothing decision;
	AR	=	physician's assignment rate;
	MPC	=	Medicare prevailing charge;
	BSF	=	Blue Shield fee;
	CRR	=	carrier rate of reduction;
	CC	=	collection costs;
	Y	=	per capita income;
	INSUR	=	health insurance coverage;
	MDCRED	=	vector of physician credentials;
	MDAGE	=	physician age;
	PRACC	=	physician practice costs;
	MDPOP	=	physician-population ratio;
	POLIT	=	physician political attitudes.