Written descriptions of four patient situations and a table of nursing actions and outcomes were presented to 47 registered nurses to investigate quantification of 185 nursing decisions about patient care. The nurses ranked the actions according to that which they considered best for the patient described, gave probabilities of the occurrence of outcomes, and assigned values to outcomes. The probability of an outcome's occurring, multiplied by the value of that outcome, and added for all outcomes of an action constituted the expected value (EV) of an action in achieving a goal. Significant agreements between the EVs and ranking of actions were obtained. The preferred action had the highest EV for 109 of the 185 decisions studied. Most decisions were justifiable in that chosen actions were desirable for achieving goals, were consistent with the nurses' knowledge of the probability of the outcomes' occurring, and were in keeping with the nurses' values for the outcomes. The findings indicated that decision theory is applicable to nursing practice, that nursing decisions can be adapted to analytical models, and that nurses can order outcomes of their actions according to their desirability and likelihood of occurrence.