7121.0 - Agricultural Commodities, Australia, 2000-01

ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 11/12/2002

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Technical Note

1 Some of the data items in this publication have undergone significant change since the release of preliminary estimates on 30 October 2001. Analysis has indicated that the early estimates were high due to problems with the survey selection frame.

2 This issue has arisen due to difficulties being experienced in tracking information about the transfer of ownership and operation of farms. Information made available by the Australian Taxation Office (ATO) through the Australian Business Register (ABR) provides an authoritative source of information about new businesses, but there is no equivalent comprehensive source of information about businesses which discontinue operations. This has led to under estimation of the number of out-of-scope and no-longer-operating units on the selection frame, an inflated estimate of operating establishments, and associated over estimation of some commodity information.

3 The problem can be illustrated by looking at the published total number of farm establishments over the last ten years. In the graph below the number of units is seen to gradually rise as the frame becomes degraded over the period from 1997-98. The dip in the graph in 2000-01 shows the effect when a full census of farm businesses was undertaken in 2000-01, and full response information became known for final results.

NUMBER OF LIVE AGRICULTURAL ESTABLISHMENTS

4 Analysis of the non-responding population from the census indicated that the intervening sample surveys were not identifying the true extent of out-of-scope or no-longer-operating units on the frame. As a result, an investigation of samples of census non-responding units was undertaken to determine the likely extent of these units among the other non-responding units. This was used to derive an adjustment factor to apply to the responding data to account for the difference between the proportion of out-of-scope or no-longer-operating units in the 'responding' population, and the proportion of out-of-scope or no-longer-operating units in the 'non-responding' population. This adjustment factor was applied to produce the estimates presented in this publication.

REVISION OF 2000-01 PRELIMINARY DATA

5 The impact of the revision process is indicated in the table below. Preliminary estimates were produced when response was at the 65% level and before the problems with the frame were identified and measured.

6 If no adjustment had been made to the census frame, estimates of the level shown in the 'unadjusted final estimate' column would have applied. This illustrates that some level of change would have occurred from the preliminary estimates with more complete response, whether or not the frame adjustments had been necessary.

7 The final column provides the 'adjusted final estimate' after taking into account the full effects of the analysis of out-of scope and no-longer-operating units.

8 The size of the change varies by 'commodity'. This reflects the varying impact of the adjustments on different survey strata arising from the investigation of samples of census non-responding units.

COMPARISON BETWEEN PRELIMINARY, UNADJUSTED FINAL AND ADJUSTED FINAL ESTIMATES FROM 2000-01 AGRICULTURAL CENSUS

Commodity	Preliminary estimate	Unadjusted final estimate	Adjusted final estimate

No. of agricultural establishments	n.a.	148,309	140,516
Area of agricultural land ('000 ha)	n.a.	461,837	455,723
Barley for grain, production ('000 t)	7,196	6,900	6,743
Grain sorghum, production ('000 t)	2,109	1,977	1,935
Oats for grain, production ('000 t)	1,131	1,080	1,050
Wheat for grain, production ('000 t)	23,766	22,587	22,108
Lupins for grain, production ('000 t)	1,140	1,076	1,055
Cereals for grain, production ('000 t)	1,717	1,701	1,657
Canola, production ('000 t)	1,905	1,813	1,775
Sugar cane cut for crushing, production ('000 t)	30,427	29,205	28,117
Cotton lint, production ('000 t)	696	678	666
Milk cattle ('000)	3,396	3,333	3,217
Meat cattle ('000)	25,372	25,047	24,504
Sheep and lambs ('000)	119,890	113,872	110,928
Pigs ('000)	2,763	2,797	2,748

REVISION OF PREVIOUS SURVEY DATA

9 This publication provides results for the 2000-01 Agricultural Census without the usual time series (three years of data). Analysis is being undertaken on the non-responding population for the previous survey years to determine a truer estimate of live populations for those years. Adjusted estimates for previous years will be published in a forthcoming issue of Agriculture, Australia (cat. no. 7113.0).