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been published each year since the establishment of OSI. As can be clearly seen, the STIR and its predecessors have increased over the years so that they now comprise the major part of OSI production. In 1949, they made up 17 percent of the total OSI depth research production; by 1968, they made up 100 percent of this production. In 1952, it was realized that much information basic to the preparation of national estimates and the evaluated STIRs was not available. Therefore the SIRAs were established as a means of pulling together and collating this information to support further analysis. Through the 1950s a fairly sizeable effort was made in this area but this effort has gradually declined as the data base and analytical capabilities have grown. A similar case is shown for the PSIRs. In the first three years of the existence of the Office, they made up 59 percent of the entire depth production; by 1964 the Office had sufficient confidence in its intelligence judgments to abolish this category. Thus, by 1968 almost all of the OSI production of in-depth reports consisted of fully analyzed studies.
Two other categories of depth production have been published by OSI. One, designated MP (Miscellaneous Publication), has included such material as listings
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