Comments on "Decentralized sequential detection

For the decentralized sequential detection problem studied by H.R. Hashemi and I.B. Rhodes (see ibid., vol.35, p.507-20, May 1989), it is pointed out that the likelihood-ratio tests are not necessarily optimal at the sensors when the decisions made by the sensors are allowed to depend on all their past observations. It is also argued that likelihood-ratio tests are indeed optimal if one restricts the decisions made by each sensor to depend on its present observation and its past decisions.<>