AbstractThe reasons for endeavouring to estimate the appropriate total research expenditure in a manufacturing industry are outlined. Three techniques are discussed using an analytical, a comparative and a synthetic approach respectively. It is pointed out that the guidance given by these three techniques differs substantially in particular situations and that more studies are needed as to the relative value of the three solutions. It is suggested that an individual company should be spending about one-fifth of its future capital requirements on R.&D. The R.&D. expenditure of the U.K. should be about 4 per cent of the gross national product.