To measure the effectiveness of any therapeutic endeavor, a set of defined outcome measurements must be performed, or the task of determining the effectiveness of any therapeutic step becomes difficult. With asthma, however, in which case it is difficult to establish the initial diagnosis, beginning a program of outcome measurements regarding any therapeutic interaction is nearly impossible. Conventional means are thwarted at the outset. One way of approaching the problem of obtaining reproducible outcomes data is to examine those areas in which measurements can be made and determine the barriers to obtaining the data. Establishing a good medical history is a critical step that, in general, is especially difficult with very young children, and tools that provide objective measurements that are used in the normal evaluation of older children are of little use in the very young child with asthma. Parts of the physical examination are difficult to perform in very young children, and findings associated with asthma can be found in other clinical states. In this age group, diary keeping suffers from the same problems and issues that are related to obtaining an accurate medical history. Barriers also exist to obtaining the best outcomes. The choice of medications for the very young child is limited; there are several typical adherence problems, and information about adverse effects is limited.