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DATA QUALITY ISSUES
(a) Non-response rates are unweighted.
(b) Not available for Australian or New Zealand citizens.
(c) New Zealand passport holders contribute to a large proportion of the non-reponse rate due to unavailable visa data.
(d) Not available for short-term movements.
INTENDED LENGTH OF STAY/TIME AWAY FROM AUSTRALIA
Non-response rates are available for these data items from November 1998. For data prior to November 1998, imputation carried out as part of processing by DIMIA has prevented reliable estimation of non-response rates for these two data items.
MAIN REASON FOR JOURNEY
Before the introduction of the redesigned passenger card in July 1998, 5% of short-term visitor arrivals, on average, were recorded as having a reason for journey of 'Other' or 'Not Stated'. This percentage rose to 14% for July, 16% in August and 29% in September 1998 as a result of processing problems. These problems have now been addressed by DIMIA, with the percentage of 'Other' and 'Not Stated' dropping in October 1998 to 8% and 7% in November 1998.
From the January 1999 issue of this publication, published figures (table 3 in this publication) referencing these three months have been revised. The revised data were calculated by estimating the number of persons responding 'Other / Not Stated' using past trends for each country of citizenship and proportionally allocating any persons in excess of the estimated 'Other / Not Stated' total amongst the remaining categories. 'Not Stated' rates are now separately available from February 1999 onwards.
STATE WHERE SPENT MOST TIME
For the months of August 1998, September 1998 and October 1998, data entry problems experienced by DIMIA caused an overstatement of the Northern Territory as the main state of stay with a corresponding understatement for the remaining states and territories. These numbers have returned in November 1998 to levels more comparable with previous years, with DIMIA indicating that they have instigated data quality procedures to address this issue.
From the January 1999 issue of this publication, published figures (table 7 in this publication) referencing these months have been revised. The revised data were calculated by estimating the number of persons indicating the Northern Territory as their main state of stay using past trends and proportionally allocating any persons in excess of these estimates amongst the remaining states and territories.
With the introduction of the new processing system from July 2001, DIMIA has provided the ABS with data on all missing values of state of stay and state of usual residence. These missing values are now imputed.
Data was imputed for non-response for state of stay/residence. For state of stay, non-responses were imputed at the category of traveller and state of clearance level. Non-response rates for state of stay are presented in the table below:
Non-responses for country of stay and country of usual residence were imputed in two stages. In the first stage, records with country of stay/residence missing were set to country of disembarkation/embarkation if a response was available. In the second stage, for remaining records where country of stay/residence was missing, values were imputed at the category of traveller, reason for journey and country of citizenship level based on responses to other cards within each subgroup. Accordingly, the level of records with data for country of stay/residence not stated has been minimised.
Change in approach to non-response state of stay for long-term visitor departures
A new procedure has been applied before imputation of a non-response to state of stay for long-term visitor departures. The procedure has two aspects. First, it detects non-reponse of state of stay for long-term visitor departures and then looks to the other outgoing passenger card boxes (box E and F on the outgoing passenger card) for a state of stay response. If no response is found, the procedure then looks for a response on the arrival card (which can be obtained by matching the arrival and departure card via a unique person identifier). Second, in the case of a correction of the box marked by a passenger (eg. a visitor marks a resident box) the state of stay will be transferred with the record or if it is still a non-response, the arrivals card will be sourced. If both these steps fail to identify a state of stay, the record then proceeds to imputation.
Country of stay
Table A3 below presents the percentage of records with country of stay/residence missing as supplied by DIMIA and prior to imputation.
(b) New Zealand passport holders contribute to a large proportion of the non-response rate due to unavailable visa data.
Table A4 shows the non-response rates for country of stay/residence following the application of the first stage of imputation.
(b) Non-response rates are weighted.
SEPTEMBER 1998 PROCESSING
A problem was experienced in the processing of OAD data for movement dates between 6 September 1998 and 16 September 1998, following the introduction of changes to DIMIA's input processing system. This problem may affect in the order of 10% of all September records used in estimation and result in incorrect details for citizenship, date of birth, sex and country of birth.
PERMANENT ARRIVALS DURING 1998
The number of permanent arrivals during July to December 1999 were revised in October 2000, as advised by DIMIA.
SEPTEMBER 1999 PROCESSING
September 1999 overseas arrivals and departures data are revised for movements from, and to, China (excl. SARs and Taiwan) and Hong Kong (SAR of China) in respect of three variables: country of birth, country of citizenship and country of residence/stay. Changes to 'country of birth' and 'country of citizenship' have been made from data supplied by DIMIA. Changes to 'country of residence/stay' have been made by assuming the average proportion of country of birth to country of residence/stay for migrants from China (excl. SARs and Taiwan) and Hong Kong (SAR of China) in September 1995 to September 1998.
SEPTEMBER QUARTER 2000 PROCESSING
A processing error was identified which affected the distribution of short-term resident departures by reason for journey for the months of August and September 2000. Affected data was re-processed, and a revised copy of table 3 for the September quarter 2000 was reissued in the October to December 2000 edition of this publication.
CHANGE TO PROCESSING OF INTENDED LENGTH OF STAY
There is evidence to suggest that when completing the intended length of stay question on the incoming passenger card (Box B), some passengers are entering their arrival/departure date or their birth date rather than their intended length of stay.
From September 2003 a rule has been implemented to the data processing system stating that if all three elements are complete (years, months and days), then the intended length of stay is to be coded to a non-response. The ABS currently assigns 'not stated' duration as a short-term movement, however a review of this procedure will be undertaken in the near future.
This procedure changes the prior data processing system which read only the years from the field on the passenger cards. The previous data processing system could have added to overestimation of the number of long-term visitor arrivals.
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