to find among their own country’s military expenditure such items that would correspond closely with those already reported by one or more of the other Contacts. 82. This approach led in turn to some improvement of the data and their comparability. However, it must be admitted that there is still a rather limited number of items for which data are available and a great deal of heterogeneity among them. 84. Concerning the construction of PPPs, however, the Group avoided using prices for items which are clearly different with regard to their military utility. To do this, considerable effort was devoted to the analysis of reported items in order to assess which of them might be of sufficiently similar military value so that it would be appropriate to use their prices for the construction of PPPs. 85. The Group’s assessment of reported data on procurement items was made even more difficult than for other items because of the generally high degree of secrecy surrounding all kinds of information on weapons and weapon systems. In addition to this basic difficulty in obtaining information on procurement items, some other examples of principal difficulties which arise in connection with comparisons of military weapons and other types of military equipment might also deserve some attention. 86. As already mentioned, the Group tried to give some guidelines to the contacts in order to harmonize their efforts to establish unit prices for complex items. The Group has, however, not had the time and necessary resources to .examine the actual assumptions on which reported data have been based. If purchasing-power parities would be constructed in the context of negotiations on a reduction of military expenditures, parties would presumably have much better possibilities to devote more efforts to this and earlier mentioned problems than this Group has been able to do. 
**Analysis**
The text discusses the difficulties in comparing military expenditure data across countries, specifically in constructing purchasing-power parities (PPPs) for military weapons and equipment. The language used is technical and economic, with a focus on the challenges of obtaining and analyzing data. This suggests that the text is related to economic issues, particularly in the context of international comparisons.

**Category**
Industry, International trade