This report examines the value for research and policy purposes of data generated by the "Pound 10 Grant Scheme" operated by Roinn na Gaeltachta in Ireland, which seeks to preserve the Irish language. The scheme was introduced in the early 30's by An Roinn Oideachais (an organization which had responsibility for the promotion of the Irish language at the time) in order to provide a direct economic incentive to families in Gaeltacht areas to maintain Irish as the language of the home. A full statistical digest is included of the available data pertaining to the scheme over the 11-year period 1973/74-1983/84 and assembles a comparable set of statistics relating to school pupil populations over the same years. Chapters 1 and 2 contain a detailed description of the operation of the scheme and bring into focus some important questions relating to the quality and consistency of the data, the very restricted information released about the scheme, and the limited range of other data to which they can be reliably related. Appendix A contains the digest of statistics. Using this combined data base, a cartographic and statistical analysis was undertaken of the patterns and trends revealed by the data at Gaeltacht, county and local levels. Chapter 3, using this data, presents a generalized picture of home bilingualism in the Gaeltacht during the period covered. Because of the limited scope of the data, no firm conclusions can be drawn from the analysis. (Contains 13 references.) (CK)