The publication of this companion volume provides an opportunity to amend certain series in my Australian Domestic Product for the years 1905/06-1911/12. These changes derive from errors in New South Wales residential investment. Since, in any event, during 1900-39 only the gross series should be used, I present simply revised gross series. (The ‘new’ tabulations contained in the detailed chapter of my book represent a stage in calculations only, subject to further substantial adjustments; and they include government housing which can only be calculated as a gross series and hence an estimate of private new residential investment cannot be made exactly.)

These estimates are based, over these years, on municipal returns of dwellings which extend back to 1886 and can be linked with the Census of 1911 and the first building permit returns of 1912. Until 1906/07, the municipal returns (other than the City of Sydney) are presented annually as at the first week of February and subject to adjustments referred to in my earlier book provide the only available source specifically dealing with changes in dwellings. These returns are not clearly labelled in the Statistical Register but their dates can be established, mainly from footnote references until 1906/07. Then until the final tabulations in 1909, there are, without warning, four different periods covered in four successive Registers. Only after re-appraising them, determined to doubt their validity did the character of the change become clear. The return of dwellings for 1906/07 is for February 1906 (many returns are out-of-date), that in the Register of the next year is, despite a misleading caption, for February 1908, not 1907. The next Register's figures relate to December 1908 and the final one to December 1909, not February 1909.

This created, then, two major errors in the original calculations yielding an excessive rise in 1907 and an excessive decline in 1909, 1910, and 1911, in linking with the Census and the building permits. To a considerable degree the scale of the error in the final gross estimates was reduced by conversion to financial years, thereby smoothing the series. But it still left an unfortunately large error over the smoothed period 1905/06-1911/12 on such a scale as to distort the figures of Australian residential investment and to affect total private investment.