Abstract: Patient pre-screening is facilitated through a system of hierarchically linked catalogues, each comprising at least one condition-descriptive entry. The hierarchy of linked catalogues is essentially tree structure in which the content of the lower-level catalogues is dependent upon particular entries in upper-level catalogues. In one embodiment, the uppermost catalogue comprises a model display of a male or female. In general, a condition-descriptive entry from an uppermost catalogue is selected. The selected condition-descriptive entry from the uppermost catalogue determines at least one lower-level catalogue that is subsequently displayed By traversing the linked catalogues in this manner, a concise diagnosis or symptom description may be quickly and accurately generated. In one embodiment of the present invention, diagnoses arrived at through the hierarchical structure include an ICS-9 code, thereby facilitating implementations of databases.