The problems considered here have cost

, a quadratic in

, wherex
ois interpreted as an initial condition and

as an unconstrained control variable. The aim is to choose

rationally when the only measurement available is the partial linear measurement

and when

should be desirable for every x
oconsistent with the measurement y
o. A dominance concept is introduced which facilitates suitable choice of

. Properties of such

are studied. The results are applied to the standard linear regulator, giving an open-loop control dependent on y
o, and to the problem of choosing the initial conditions for dynamic compensators.