"Injections produce the most negative responses of any procedure for a child (Faust, 1953; Eland and Anderson, 1977) and yet most immunizations are injectable and mandatory for all pre-school children. Noxious intrusive procedures such as injections are too frequently performed on children by health professionals without considering the child's feelings. Nurses are the health professionals most frequently present to help the child cope with the experience of pain (McCaffrey, 1972), which is a subjective personal experience (Szasz, 1975). Since the primary focus of nursing is the subjective experience (McBride, 1969) such as the pain from an injection, the child facing this procedure should receive nursing assistance. Orem stated that nursing is required only when there is a deficit in ability to care for self. Parents ordinarily act as child-care agents and provide this self-care as the child's developmental level requires it. Thus it is only when there is a deficit in the parent's ability to provide therapeutic self care that nursing assistance is required. This assistance in the form of preparing the child for a painful experience benefits both child and parent (Orem, 1971), particularly the parent concerned about the hurt to the child (Szasz, 1959). Nursing agency includes developing methods of preparing the pre-school child for a painful procedure, assisting the child in communicating pain intensity, and being aware of factors influencing the response to pain. There are pain measurement tools for adults and many studies have been done using these tools. However, there are few tools to help the child communicate the intensity of pain felt. The measurement tool (Hester, 1976) chosen for this study had been found useful in helping the child 4½ to 6½ years of age describe pain intensity. It also had the advantage of providing a visual component for the child with limited verbal ability, was easily available from a pocket, could be administered in a brief time period, and had a structured procedure thus controlling investigator bias. Hester's recommendation for further study and refinement of the tool prompted comparison with another tool. The investigator developed a comparative tool and the Happstick booklet using information gained in other pain investigations. Recalling the usefulness of visual preparation for the child (Vaughn, 1957; Vernon, 1974) the investigator also gave recognition to the many elements involved in pain experience, including the sensory and the emotion components (Johnson and Rice, 1974). A study in which various emotional states were expressed through use of 'pin-man' type figures (Reitman and Robertson, 1950) and the visual perception studies of Fantz (1965) that noted the child's early preference for the human face, led to combining all these factors for a measurement tool and preparation procedure. Advantages of these types of drawings are that they have no age, sex or race--giving them universality. Such a portable tool could have potential as a device to help the child communicate pain intensity in other nursing."--Introduction.