Mailing Address: Giácomo Balbinotto Neto e Everton Nunes da Silva • Av. João Pessoa 52, PPGE, 90.040-000, Porto Alegre, RS Brazil. E-mail: [email protected] e [email protected]

Mailing address: Adriana Lopes Latado • Rua Rosa dos Ventos, 39/1002 Ed. Pedra Alta – Brotas 40286-040 Salvador, BA Brazil E-mail:[email protected], [email protected]

Mailing Address: Vera D. Aiello • InCor – Av. Dr. Enéas de Carvalho Aguiar, 44. Postal Code 05403-000, São Paulo, SP – Brazil E-mail: [email protected]

Mailing Address: Vera Demarchi Aiello • bloco I, Cerqueira César. Postal Code 05403-000, São Paulo, SP Brazil E-mail: [email protected], [email protected]

Mailing address: Edmar Atik • Rua Dona Adma Jafet, 74 cj 73 Bela Vista 01308-050 São Paulo, SP, Brazil E-mail: [email protected]

Mailing address: Márcia de Melo Barbosa • Al Conde do Rio Pardo, 288, Vila do Conde, 34.000-000, Nova Lima, MG Brazil E-mail: [email protected], [email protected]

OBJECTIVES The effects of incentive size on physicians' response rates to a mail survey were determined. METHODS One thousand US primary care physicians were assigned randomly to receive a survey with either a $5 bill or a $2 bill as an incentive. For each of the two incentive groups, the overall response rate for three mailing waves, the total cost, and the total cost per usable response wer...